IMAPD.CONF(5)

NAME
imapd.conf - Cyrus IMAP documentation

IMAP configuration file

DESCRIPTION
/etc/imapd.conf is the configuration file for the Cyrus IMAP server. It defines local parameters for IMAP.

Each line of the /etc/imapd.conf file has the form
    option: value

    where option is the name of the configuration option being set and value is the value that the configuration option is being set to.

    Although there is no limit to the length of a line, a ``\'' (backslash) character may be used as the last character on a line to force it to continue on the next one. No additional whitespace is inserted before or after the ``\''. Note that a line that is split using ``\'' character(s) is still considered a single line.

For example
    option:\ value1 value2 \ value3

is equivalent to
    option: value1 value2 value3

    Blank lines and lines beginning with ``#'' are ignored.

    For boolean and enumerated options, the values ``yes'', ``on'', ``t'', ``true'' and ``1'' turn the option on, the values ``no'', ``off'', ``f'', ``false'' and ``0'' turn the option off.

    Duration options take the form of a number followed by a unit, for example 32m (32 minutes). Units are d (days), h (hours), m (minutes) and s (seconds). Multiple units can be combined and will be summed together, for example 1h30m is equivalent to 90m. If no unit is specified, an option-specific backward-compatible default unit is assumed (documented on an option-by-option basis). These are simple time units: 1d=24h, 1h=60m, 1m=60s (daylight savings, timezones, leap adjustments, etc are not considered).

    Byte size options take the form of a number followed by a unit, for example 1KiB (1 kibibyte). Units are B (bytes), KiB (kibibytes), MiB (mebibytes), and GiB (gibibytes), which may also be spelt KB, MB, and GB. Units are parsed without regard to case. Note that regardless of spelling, these units are always powers of 2, and never metric. That is, 1GiB = 1024MiB, 1MiB = 1024KiB, 1KiB = 1024B. If no unit is specified, an option-specific backward-compatible default unit is assumed (documented on an option-by-option basis).

FIELD DESCRIPTIONS
The sections below detail options that can be placed in the /etc/imapd.conf file, and show each option's default value. Some options have no default value, these are listed with ``<no default>''. Some options default to the empty string, these are listed with ``<none>''.

acl_admin_implies_write: 0 If enabled, any user with the admin ACL on a mailbox implicitly gets the ability to write to that mailbox as well.

addressbookprefix: #addressbooks The prefix for the addressbook mailboxes hierarchies. The hierarchy delimiter will be automatically appended. The public addressbook hierarchy will be at the toplevel of the shared namespace. A user's personal addressbook hierarchy will be a child of their Inbox.

admins: <empty string> The list of userids with administrative rights. Separate each userid with a space. Sites using Kerberos authentication may use separate "admin" instances.

Note that accounts used by users should not be administrators. Administrative accounts should not receive mail. That is, if user "jbRo" is a user reading mail, he should not also be in the admins line. Some problems may occur otherwise, most notably the ability of administrators to create top-level mailboxes visible to users, but not writable by users.

afspts_localrealms: <none> The list of realms which are to be treated as local, and thus stripped during identifier canonicalization (for the AFSPTS ptloader module). This is different from loginrealms in that it occurs later in the authorization process (as the user id is canonified for PTS lookup).

afspts_mycell: <none> Cell to use for AFS PTS lookups. Defaults to the local cell.

allowallsubscribe: 0 Allow subscription to nonexistent mailboxes. This option is typically used on backend servers in a Murder so that users can subscribe to mailboxes that don't reside on their "home" server. This option can also be used as a workaround for IMAP clients which don't play well with nonexistent or unselectable mailboxes (e.g., Microsoft Outlook).

allowanonymouslogin: 0 Permit logins by the user "anonymous" using any password. Also allows use of the SASL ANONYMOUS mechanism.

allowapop: 1 Allow use of the POP3 APOP authentication command.

Note that this command requires that SASL is compiled with APOP support, that the plaintext passwords are available in a SASL auxprop backend (e.g., sasldb), and that the system can provide enough entropy (e.g., from /dev/urandom) to create a challenge in the banner.

allowdeleted: 0 Allow access to deleted and expunged data via vendor.cmu-* access.

allownewnews: 0 Allow use of the NNTP NEWNEWS command.

Note that this is a very expensive command and should only be enabled when absolutely necessary.

allowplaintext: 0 If enabled, allows the use of cleartext passwords on the wire.

By default, the use of cleartext passwords requires a TLS/SSL encryption layer to be negotiated prior to any cleartext authentication mechanisms being advertised or allowed. To require a TLS/SSL encryption layer to be negotiated prior to ANY authentication, see the tls_required option.

allowsetacl: 1 Defaults to enabled. If disabled, disallows the use of the SETACL command at all via IMAP.

allowspecialusesubfolder: 0 If enabled, allows special-use folders to be moved into subfolders

By default, cyrus does not allow a special-use folder to be moved or renamed if the new folder is not a direct folder of the users INBOX. This was implemented to prevent clients renaming Sent to Trash/Sent, which would confused other clients.

allowstarttls: 0 If enabled, allows upgrading a plaintext connection to use TLS (a.k.a opportunistic TLS) via a protocol specific command/mechanism. IMAP, LMTP, NNTP, and ManageSieve use the STARTTLS command. POP3 uses the STLS command. HTTP uses the Upgrade header field.

allowusermoves: 0 Allow moving user accounts (with associated meta-data) via RENAME or XFER.

Note that measures should be taken to make sure that the user being moved is not logged in, and cannot login during the move. Failure to do so may result in the user's meta-data (seen state, subscriptions, etc) being corrupted or out of date.

altnamespace: 1 Use the alternate IMAP namespace, where personal folders reside at the same level in the hierarchy as INBOX.

This option ONLY applies where interaction takes place with the client/user. Currently this is limited to the IMAP protocol (imapd) and Sieve scripts (lmtpd). This option does NOT apply to admin tools such as cyradm (admins ONLY), reconstruct, quota, etc., NOR does it affect LMTP delivery of messages directly to mailboxes via plus-addressing. The default changed in 3.0 from off to on.

altprefix: Alt Folders Alternative INBOX spellings that can't be accessed in altnamespace otherwise go under here.

annotation_db: twoskip The cyrusdb backend to use for mailbox annotations.

Allowed values: skiplist, twoskip, zeroskip

annotation_db_path: <none> The absolute path to the annotations db file. If not specified, will be configdirectory/annotations.db

anyoneuseracl: 1 Should non-admin users be allowed to set ACLs for the 'anyone' user on their mailboxes? In a large organization this can cause support problems, but it's enabled by default.

annotation_allow_undefined: 0 Allow clients to store values for entries which are not defined either by Cyrus or in the annotations_definitions file.

annotation_definitions: <none> File containing external (third-party) annotation definitions.

Each line of the file specifies the properties of an annotation and has the following form: name, scope, attrib-type, proxy-type, attrib-names, acl

name
    is the hierarchical name as in RFC 5257 <https://datatracker.ietf.org/doc/html/rfc5257.html> or RFC 5464 <https://datatracker.ietf.org/doc/html/rfc5464.html> (in the latter case, without the leading /shared or /private). For example, /vendor/acme/blurdybloop.

scope
    specifies whether the annotation is for the server, a mailbox, or a message.

attrib-type
    specifies the attribute data type, which is used only to check the string value passed by clients when setting annotations. The attrib-type is one of:

string
    any value is accepted.

content-type
    this obsolete data type, which was useful for early drafts of the standard, is accepted but silently translated to string.

boolean
    only the strings "true" or "false" are accepted. Checking is case-insensitive but the value is forced to lowercase.

int integers are accepted.

uint
    non-negative integers are accepted.

proxy-type
    specifies whether this attribute is for the backend or proxy servers or both (proxy_and_backend)

attrib-names
    is the space-separated list of available attributes for the annotation. Possible attribute names are value.shared, value.priv, and value (which permits both value.priv and value.shared). The attribute names size, size.shared, and size.priv are accepted but ignored; these attributes are automatically provided by the server if the corresponding value attribute is specified. Some obsolete attributes, which were defined early drafts of the standard, are accepted and ignored with a warning.

extra-permissions
    is the extra ACL permission bits required for setting this annotation, in standard IMAP ACL permission bit string format. Note that this is in addition to the permission bits specified in RFC 5257 <https://datatracker.ietf.org/doc/html/rfc5257.html> and RFC 5464 <https://datatracker.ietf.org/doc/html/rfc5464.html>, so leaving this field empty is harmless. Note also that there is no way to specify that an annotation can only be set by an admin user; in particular the a permission bit does not achieve this.

    Blank lines and lines beginning with ``#'' are ignored.

    annotation_callout: <none> The pathname of a callout to be used to automatically add annotations or flags to a message when it is appended to a mailbox. The path can be either an executable (including a script), or a UNIX domain socket.

    annotation_callout_disable_append: 0 Disables annotations on append with xrunannotator.

    annotation_enable_legacy_commands: 0 Whether to enable the legacy GETANNOTATION/SETANNOTATION commands. These commands are deprecated and will be removed in the future, but might be useful in the meantime for supporting old clients that do not implement the RFC 5464 <https://datatracker.ietf.org/doc/html/rfc5464.html> IMAP METADATA extension.

    aps_topic: <none> Topic for Apple Push Service registration.

    aps_topic_caldav: <none> Topic for Apple Push Service registration for CalDAV.

    aps_topic_carddav: <none> Topic for Apple Push Service registration for CardDAV.

    aps_expiry: 1d Time after which a CalDAV/CardDAV push subscription will expire. A client will have to refresh the subscription in order to continue to receive push notifications.

    archive_enabled: 0 Is archiving enabled for this server. You also need to have an archivepartition for the mailbox. Archiving allows older email to be stored on slower, cheaper disks - even within the same mailbox, as distinct from partitions.

    archive_days: <none> Deprecated in favour of archive_after.

    archive_after: 7d The duration after which to move messages to the archive partition if archiving is enabled.

    For backward compatibility, if no unit is specified, days is assumed.

    archive_maxsize: 1024 K The size of the largest message that won't be archived immediately.

    For backward compatibility, if no unit is specified, kibibytes is assumed.

    archive_keepflagged: 0 If set, messages with the \Flagged system flag won't be archived, provided they are smaller than archive_maxsize.

    archivepartition-name: <none> The pathname of the archive partition name, corresponding to spool partition partition-name. For any mailbox residing in a directory on partition-name, the archived messages will be stored in a corresponding directory on archivepartition-name. Note that not every partition-name option is strictly required to have a corresponding archivepartition-name option, but that without one there's no benefit to enabling archiving.

    auditlog: 0 Should cyrus output log entries for every action taken on a message file or mailboxes list entry? It's noisy so disabled by default, but can be very useful for tracking down what happened if things look strange.

    auth_mech: unix The authorization mechanism to use.

    Allowed values: unix, pts, krb5, mboxgroups

    autocreateinboxfolders: <none> Deprecated in favor of autocreate_inbox_folders.

    autocreatequota: <none> Deprecated in favor of autocreate_quota.

    autocreatequotamsg: -1 Deprecated in favor of autocreate_quota_messages.

    autosievefolders: <none> Deprecated in favor of autocreate_sieve_folders.

    generate_compiled_sieve_script: 0 Deprecated in favor of autocreate_sieve_script_compile.

    autocreate_sieve_compiled_script: <none> Deprecated in favor of autocreate_sieve_script_compiled.

    autosubscribeinboxfolders: <none> Deprecated in favor of autocreate_subscribe_folders.

    autosubscribesharedfolders: <none> Deprecated in favor of autocreate_subscribe_sharedfolders.

    autosubscribe_all_sharedfolders: 0 Deprecated in favor of autocreate_subscribe_sharedfolders_all.

    autocreate_acl: <none> If folders are to be created by autocreate_inbox_folders, this setting can be used to apply additional ACLs to the autocreated folders. The syntax is "autocreate_acl folder identifier rights", where folder must match one of the autocreate_inbox_folders folders, identifier must be a valid cyrus identifier, and rights must be a valid cyrus rights string. Multiple identifier|rights pairs can be assigned to a single folder by providing this setting multiple times.

    For example, "autocreate_acl Plus anyone p" would allow lmtp delivery to a folder named "Plus".

    autocreate_inbox_folders: <none> If a user does not have an INBOX already, and the INBOX is to be created, create the list of folders in this setting as well. autocreate_inbox_folders is a list of INBOX's subfolders separated by a "|", that are automatically created by the server under the following two scenarios. Leading and trailing whitespace is stripped, so "Junk | Trash" results in two folders: "Junk" and "Trash". See also the xlist-flag option, for setting special-use flags on autocreated folders.

    INBOX folders are created under both the following conditions:

1.  The user logins via the IMAP or the POP3 protocol. autocreate_quota option must have a value of zero or greater.

2.  A message arrives for the user through the lmtpd(8). autocreate_post option must be enabled.

    autocreate_post: 0 If enabled, when lmtpd(8) receives an incoming mail for an INBOX that does not exist, then the INBOX is automatically created by lmtpd(8) and delivery of the message continues.

    autocreate_quota: -1 If set to a value of zero or higher, users have their INBOX folders created upon a successful login event or upon lmtpd(8) message delivery if autocreate_post is enabled, provided their INBOX did not yet already exist.

    The user's quota is set to the value if it is greater than zero, otherwise the user has unlimited quota.

    Note that quota has kibibyte granularity. Values specified here will be truncated to the nearest whole kibibyte.

    For backward compatibility, if no unit is specified, kibibytes is assumed.

    autocreate_quota_messages: -1 If set to a value of zero or higher, users who have their INBOX folders created upon a successful login event (see autocreate_quota), or upon lmtpd(8) message delivery if autocreate_post is enabled, receive the message quota configured in this option.

    The default of -1 disables assigning message quota.

    For consistency with autocreate_quota, a value of zero is treated as unlimited message quota, rather than a message quota of zero.

    autocreate_sieve_folders: <none> A "|" separated list of subfolders of INBOX that will be automatically created, if requested by a sieve filter, through the "fileinto" action. The default is to create no folders automatically.

    Leading and trailing whitespace is stripped from each folder, so a setting of "Junk | Trash" will create two folders: "Junk" and "Trash".

    autocreate_sieve_script: <none> The full path of a file that contains a sieve script. This script automatically becomes a user's initial default sieve filter script.

    When this option is not defined, no default sieve filter is created. The file must be readable by the Cyrus daemon.

    autocreate_sieve_script_compile: 0 If set to yes and no compiled sieve script file exists, the sieve script which is compiled on the fly will be saved in the file name that autocreate_sieve_compiledscript option points to. In order a compiled script to be generated, autocreate_sieve_script and autocreate_sieve_compiledscript must have valid values.

    autocreate_sieve_script_compiled: <none> The full path of a file that contains a compiled in bytecode sieve script. This script automatically becomes a user's initial default sieve filter script. If this option is not specified, or the filename doesn't exist then the script defined by autocreate_sieve_script is compiled on the fly and installed as the user's default sieve script.

    autocreate_subscribe_folders: <none> A list of folder names, separated by "|", that the users get automatically subscribed to, when their INBOX is created. These folder names must have been included in the autocreateinboxfolders option of the imapd.conf.

    autocreate_subscribe_sharedfolders: <none> A list of shared folders (bulletin boards), separated by "|", that the users get automatically subscribed to, after their INBOX is created. The shared folder must have been created and the user must have the required permissions to get subscribed to it. Otherwise, subscribing to the shared folder fails.

    autocreate_subscribe_sharedfolders_all: 0 If set to yes, the user is automatically subscribed to all shared folders, one has permission to subscribe to.

    autocreate_users: anyone A space separated list of users and/or groups that are allowed their INBOX to be automatically created.

    autoexpunge: 0 If set to yes, then all Deleted messages will be automatically expunged whenever an index is closed, whether CLOSE, UNSELECT, SELECT or on disconnect.

    backuppartition-name: <none> Deprecated. No longer used.

    backup_compact_minsize: 0 Deprecated. No longer used.

    backup_compact_maxsize: 0 Deprecated. No longer used.

    backup_compact_work_threshold: 1 Deprecated. No longer used.

    backup_staging_path: <none> Deprecated. No longer used.

    backup_retention_days: <none> Deprecated. No longer used.

    backup_retention: 7d Deprecated. No longer used.

    backup_db: twoskip Deprecated. No longer used.

    backup_db_path: <none> Deprecated. No longer used.

    backup_keep_previous: 0 Deprecated. No longer used.

    boundary_limit: 1000 messages are parsed recursively and a deep enough MIME structure can cause a stack overflow. Do not parse deeper than this many layers of MIME structure. The default of 1000 is much higher than any sane message should have.

    caldav_accept_invalid_rrules: 0 Accept invalid RRULEs (e.g. FREQ=WEEKLY;BYMONTHDAY=15) rather than rejecting them as errors.

    caldav_alarm_db_path: <none> Path to the caldav_alarm database file - defaults to $confdir/caldav_alarm.sqlite3 if not set

    caldav_alarm_support_components: VEVENT VTODO Space-separated list of iCalendar component types for which calalarmd generates alarms. Allowed values: VEVENT, VTODO

    caldav_alarm_suppress_file: <none> If this file exists, calalarmd will not process events

    caldav_allowattach: 1 Enable managed attachments support on the CalDAV server.

    caldav_allowcalendaradmin: 0 Enable per-user calendar administration web UI on the CalDAV server.

    caldav_allowscheduling: on Enable calendar scheduling operations. If set to "apple", the server will emulate Apple CalendarServer behavior as closely as possible. Allowed values: off, on, apple

    caldav_create_attach: 1 Create the 'Attachments' collection if it doesn't already exist.

    caldav_create_default: 1 Create the 'Default' calendar if it doesn't already exist.

    caldav_create_sched: 1 Create the 'Inbox' and 'Outbox' calendars if they don't already exist.

    caldav_historical_age: 7d How long after an occurrence of event or task has concluded that it is considered 'historical'. Changes to historical occurrences of events or tasks WILL NOT have invite or reply messages sent for them. A negative value means that events and tasks are NEVER considered historical.

    For backward compatibility, if no unit is specified, days is assumed.

    caldav_maxdatetime: 20380119T031407Z The latest date and time accepted by the server (ISO format). This value is also used for expanding non-terminating recurrence rules.

    Note that increasing this value will require the DAV databases for calendars to be reconstructed with the dav_reconstruct utility in order to see its effect on serer-side time-based queries.

    caldav_mindatetime: 19011213T204552Z The earliest date and time accepted by the server (ISO format).

    caldav_realm: <none> The realm to present for HTTP authentication of CalDAV resources. If not set (the default), the value of the "servername" option will be used.

    calendarprefix: #calendars The prefix for the calendar mailboxes hierarchies. The hierarchy delimiter will be automatically appended. The public calendar hierarchy will be at the toplevel of the shared namespace. A user's personal calendar hierarchy will be a child of their Inbox.

    calendar_default_displayname: personal The displayname to be used when creating a user's 'Default' calendar.

    calendar_user_address_set: <none> Space-separated list of domains corresponding to calendar user addresses for which the server is responsible. If not set (the default), the value of the "defaultdomain" option will be used.

    calendar_component_set: VEVENT VTODO VJOURNAL VFREEBUSY VAVAILABILITY VPOLL Space-separated list of iCalendar component types that calendar object resources may contain in a calendar collection. This restriction is only set at calendar creation time and only if the CalDAV client hasn't specified a restriction in the creation request. Allowed values: VEVENT, VTODO, VJOURNAL, VFREEBUSY, VAVAILABILITY, VPOLL

    calendar_minimum_alarm_interval: 5m The minimum allowed interval between alarms for a recurring event. Primarily used to suppress alarms for MINUTELY and SECONDLY recurrences. The minimum value is 0, which will allow all alarms.

    calendar_suppress_duplicate_alarms: 1 Suppress duplicate calendar alarms in calalarmd. If this is set, then at most one alarm notification is sent for any given alarm action, point in time and calendar event.

    carddav_allowaddmember: 0 Enable support for POST add-member on the CardDAV server.

    carddav_allowaddressbookadmin: 0 Enable per-user addressbook administration web UI on the CardDAV server.

    carddav_realm: <none> The realm to present for HTTP authentication of CardDAV resources. If not set (the default), the value of the "servername" option will be used.

    carddav_repair_vcard: 0 If enabled, VCARDs with invalid content are attempted to be repaired during creation.

    chatty: 0 If yes, syslog tags and commands for every IMAP command, mailboxes for every LMTP connection, every POP3 command, etc.

    client_bind: 0 If enabled, a specific IP will be bound when performing a client connection. client_bind_name is used if it is set, otherwise servername is used. This is useful on multi-homed servers where Cyrus should not use other services' interfaces.

    If not enabled (the default), no bind will be performed. Client connections will use an IP chosen by the operating system.

    client_bind_name: <none> IPv4, IPv6 address or hostname to bind for client connections when client_bind is enabled. If not set (the default), servername will be used.

    client_timeout: 10s Time to wait before returning a timeout failure when performing a client connection (e.g. in a murder environment).

    For backward compatibility, if no unit is specified, seconds is assumed.

    commandmintimer: <none> Time in floating point seconds. Any imap command that takes longer than this time is logged.

    configdirectory: <none> The pathname of the IMAP configuration directory. This field is required.

    createonpost: 0 Deprecated in favor of autocreate_post.

    conversations: 0 Enable the XCONVERSATIONS extensions. Extract conversation tracking information from incoming messages and track them in per-user databases.

    conversations_counted_flags: <none> space-separated list of flags for which per-conversation counts will be kept. Note that you need to reconstruct the conversations database with ctl_conversationsdb if you change this option on a running server, or the counts will be wrong.

    conversations_db: skiplist The cyrusdb backend to use for the per-user conversations database.

    Allowed values: skiplist, sql, twoskip, zeroskip

    conversations_expire_days: <none> Deprecated in favor of conversations_expire_after.

    conversations_expire_after: 90d How long the conversations database keeps the message tracking information needed for receiving new messages in existing conversations.

    For backward compatibility, if no unit is specified, days is assumed.

    conversations_keep_existing: 1 During conversations cleanup, don't clean up if there are still existing emails with one of the mentioned CIDs.

    conversations_max_thread: 100 maximum size for a single thread. Threads will split if they have this many messages in them and another message arrives.

    conversations_max_guidrecords: 5000 maximum records with the same guid. This is just a sanity check to stop the same email being added and removed over and over.

    conversations_max_guidexists: 100 maximum records with the same guid. This maps to "labels", so with the default of 100, you can only have 100 labels on an email in JMAP.

    conversations_max_guidinfolder: 10 maximum records with the same guid in the same folder. You can't do this via JMAP, but could via IMAP. The default of 10 should be heaps normally!

    crossdomains: 0 Enable cross domain sharing. This works best with alt namespace and unix hierarchy separators on, so you get Other <Users/foo@example.com/>...

    crossdomains_onlyother: 0 only show the domain for users in other domains than your own (for backwards compatibility if you're already sharing.

    cyrus_group: <none> The name of the group Cyrus services will run as. If not configured, the primary group of cyrus_user will be used. Can be further overridden by setting the $CYRUS_GROUP environment variable.

    cyrus_user: <none> The username to use as the 'cyrus' user. If not configured, the compile time default will be used. Can be further overridden by setting the $CYRUS_USER environment variable.

    davdriveprefix: #drive The prefix for the DAV storage mailboxes hierarchies. The hierarchy delimiter will be automatically appended. The public storage hierarchy will be at the toplevel of the shared namespace. A user's personal storage hierarchy will be a child of their Inbox.

    davnotificationsprefix: #notifications The prefix for the DAV notifications hierarchy. The hierarchy delimiter will be automatically appended. The public notifications hierarchy will be at the toplevel of the shared namespace. A user's personal notifications hierarchy will be a child of their Inbox.

    dav_realm: <none> The realm to present for HTTP authentication of generic DAV resources (principals). If not set (the default), the value of the "servername" option will be used.

    dav_lock_timeout: 20s The maximum time to wait for a write lock on the per-user DAV database before timeout. For HTTP requests, the HTTP status code 503 is returned if the lock can not be obtained within this time.

    For backward compatibility, if no unit is specified, seconds is assumed.

    debug: 0 If enabled, allow syslog() to pass LOG_DEBUG messages.

    This can be toggled for a running process by sending it SIGUSR1.

    debug_command: <none> Debug command to be used by processes started with -D option. The string is a C format string that gets 3 options: the first is the name of the executable (as specified in the cmd parameter in cyrus.conf). The second is the pid (integer) and the third is the service ID. Example: /usr/local/bin/gdb /usr/cyrus/bin/%s %d

    debug_log_sync_partition_choice: 0 If enabled, replication will log which partition it chose for staging. This is mainly useful for regression testing the sync_client -a switch.

    debug_slowio: 0 If enabled, I/O operations will be artificially slowed down. This option has no effect unless Cyrus was compiled with the --enable-debug-slowio configure argument. This is mainly useful for testing certain edge case handling.

    debug_writefail_guid: <none> If set, any arriving message with this guid will fail as if the underlying disk write had failed, pretending to be a disk full condition. This is mainly useful for regression testing certain edge case handling. Currently only implemented for replication uploads.

    defaultacl: anyone lrs The Access Control List (ACL) placed on a newly-created (non-user) mailbox that does not have a parent mailbox.

    defaultdomain: internal The default domain for virtual domain support.

    defaultpartition: <none> The partition name used by default for new mailboxes. If not specified, the partition with the most free space will be used for new mailboxes.

    Note that the partition specified by this option must also be specified as partition-name, where you substitute 'name' for the alphanumeric string you set defaultpartition to.

    defaultsearchtier: <empty string> Name of the default tier that messages will be indexed to. Search indexes can be organized in tiers to allow index storage in different directories and physical media. See the man page of squatter for details. The default search tier also requires the definition of an according searchtierpartition-name entry.

    This option MUST be specified for xapian search.

    defaultserver: <none> The backend server name used by default for new mailboxes. If not specified, the server with the most free space will be used for new mailboxes.

    deletedprefix: DELETED With delete_mode set to delayed, the deletedprefix setting defines the prefix for the hierarchy of deleted mailboxes.

    The hierarchy delimiter will be automatically appended.

    delete_mode: delayed The manner in which mailboxes are deleted. In the default delayed mode, mailboxes that are being deleted are renamed to a special mailbox hierarchy under the deletedprefix, to be removed later by cyr_expire(8).

    In immediate mode, the mailbox is removed from the filesystem immediately.

    Allowed values: immediate, delayed

    delete_unsubscribe: 0 Whether to also unsubscribe from mailboxes when they are deleted. Note that this behaviour contravenes RFC 3501 <https://datatracker.ietf.org/doc/html/rfc3501.html> section 6.3.9, but may be useful for avoiding user/client software confusion.

    deleteright: c Deprecated - only used for backwards compatibility with existing installations. Lists the old RFC 2086 <https://datatracker.ietf.org/doc/html/rfc2086.html> right which was used to grant the user the ability to delete a mailbox. If a user has this right, they will automatically be given the new 'x' right.

    disable_user_namespace: 0 Preclude list command on user namespace. If set to 'yes', the LIST response will never include any other user's mailbox. Admin users will always see all mailboxes.

    disable_shared_namespace: 0 Preclude list command on shared namespace. If set to 'yes', the LIST response will never include any non-user mailboxes. Admin users will always see all mailboxes.

    disconnect_on_vanished_mailbox: 0 If enabled, IMAP/POP3/NNTP clients will be disconnected by the server if the currently selected mailbox is (re)moved by another session. Otherwise, the missing mailbox is treated as empty while in use by the client.

    ischedule_dkim_domain: <none> The domain to be reported as doing iSchedule DKIM signing.

    ischedule_dkim_key_file: <none> File containing the private key for iSchedule DKIM signing.

    ischedule_dkim_required: 1 A DKIM signature is required on received iSchedule requests.

    ischedule_dkim_selector: <none> Name of the selector subdividing the domain namespace. This specifies the actual key used for iSchedule DKIM signing within the domain.

    duplicate_db: twoskip The cyrusdb backend to use for the duplicate delivery suppression and sieve. Allowed values: skiplist, sql, twoskip, zeroskip

    duplicate_db_path: <none> The absolute path to the duplicate db file. If not specified, will be configdirectory/deliver.db

    duplicatesuppression: 1 If enabled, lmtpd will suppress delivery of a message to a mailbox if a message with the same message-id (or resent-message-id) is recorded as having already been delivered to the mailbox. Records the mailbox and message-id/resent-message-id of all successful deliveries.

    event_content_inclusion_mode: standard The mode in which message content may be included with MessageAppend and MessageNew. "standard" mode is the default behavior in which message is included up to a size with the notification. In "message" mode, the message is included and may be truncated to a size. In "header" mode, it includes headers truncated to a size. In "body" mode, it includes body truncated to a size. In "headerbody" mode, it includes full headers and body truncated to a size. Allowed values: standard, message, header, body, headerbody

    event_content_size: 0 Truncate the message content that may be included with MessageAppend and MessageNew. Set 0 to include the entire message itself.

    If no unit is specified, bytes is assumed.

    event_exclude_flags: <none> Don't send event notification for given IMAP flag(s).

    event_exclude_specialuse: \Junk Don't send event notification for folder with given special-use attributes. Set ALL for any folder.

    event_extra_params: timestamp Space-separated list of extra parameters to add to any appropriated event.

    Allowed values: bodyStructure, clientAddress, diskUsed, flagNames, messageContent, messageSize, messages, modseq, service, timestamp, uidnext, vnd.cmu.midset, vnd.cmu.unseenMessages, vnd.cmu.envelope, vnd.cmu.sessionId, vnd.cmu.mailboxACL, vnd.cmu.mbtype, vnd.cmu.davFilename, vnd.cmu.davUid, vnd.fastmail.clientId, vnd.fastmail.sessionId, vnd.fastmail.convExists, vnd.fastmail.convUnseen, vnd.fastmail.cid, vnd.fastmail.counters, vnd.fastmail.jmapEmail, vnd.fastmail.jmapStates, vnd.cmu.emailid, vnd.cmu.threadid, vnd.cmu.visibleUsers

    event_groups: message mailbox Space-separated list of groups of related events to turn on notification.

    Allowed values: message, quota, flags, access, mailbox, subscription, calendar, applepushservice, jmap

    event_notifier: <none> Notifyd(8) method to use for "EVENT" notifications which are based on the RFC 5423 <https://datatracker.ietf.org/doc/html/rfc5423.html>. If not set, "EVENT" notifications are disabled.

    expunge_mode: delayed The mode in which messages (and their corresponding cache entries) are expunged. "semidelayed" mode is the old behavior in which the message files are purged at the time of the EXPUNGE, but index and cache records are retained to facilitate QRESYNC. In "delayed" mode, which is the default since Cyrus 2.5.0, the message files are also retained, allowing unexpunge to rescue them. In "immediate" mode, both the message files and the index records are removed as soon as possible. In all cases, nothing will be finally purged until all other processes have closed the mailbox to ensure they never see data disappear under them. In "semidelayed" or "delayed" mode, a later run of "cyr_expire" will clean out the retained records (and possibly message files). This reduces the amount of I/O that takes place at the time of EXPUNGE and should result in greater responsiveness for the client, especially when expunging a large number of messages. Allowed values: immediate, semidelayed, delayed

    failedloginpause: 3s Time to pause after a failed login.

    For backward compatibility, if no unit is specified, seconds is assumed.

    fatals_abort: 0 If enabled, when fatal errors are detected, Cyrus will call abort() to produce a core dump, unless the error was due to a misbehaving client. This is useful if you have the ability to debug a core dump.

    If not enabled (the default), the process will exit normally with an error code.

    flushseenstate: 1 Deprecated. No longer used.

    foolstupidclients: 0 If enabled, only list the personal namespace when a LIST "*" is performed (it changes the request to a LIST "INBOX*").

    force_sasl_client_mech: <none> Force preference of a given SASL mechanism for client side operations (e.g., murder environments). This is separate from (and overridden by) the ability to use the <host shortname>_mechs option to set preferred mechanisms for a specific host.

    global_lock: 1 Use a global shared lock for ALL writes, allowing the global lock wrapper tool to freeze the world

    fulldirhash: 0 If enabled, uses an improved directory hashing scheme which hashes on the entire username instead of using just the first letter as the hash. This changes hash algorithm used for quota and user directories and if hashimapspool is enabled, the entire mail spool.

    Note that this option CANNOT be changed on a live system. The server must be quiesced and then the directories moved with the rehash utility.

    hashimapspool: 0 If enabled, the partitions will also be hashed, in addition to the hashing done on configuration directories. This is recommended if one partition has a very bushy mailbox tree.

    hostname_mechs: <none> Force a particular list of SASL mechanisms to be used when authenticating to the backend server hostname (where hostname is the short hostname of the server in question). If it is not specified it will query the server for available mechanisms and pick one to use. - Cyrus Murder

    hostname_password: <none> The password to use for authentication to the backend server hostname (where hostname is the short hostname of the server) - Cyrus Murder

    httpallowcompress: 1 If enabled, the server will compress response payloads if the client indicates that it can accept them. Note that the compressed data will appear in telemetry logs, leaving only the response headers as human-readable.

    httpallowcors: <none> A wildmat pattern specifying a list of origin URIs ( scheme "://" host [ ":" port ] ) that are allowed to make Cross-Origin Resource Sharing (CORS) requests on the server. By default, CORS requests are disabled.

    Note that the scheme and host should both be lowercase, the port should be omitted if using the default for the scheme (80 for http, 443 for https), and there should be no trailing '/' (e.g.: "<http://www.example.com:8080>", "<https://example.org>").

    httpallowtrace: 0 Allow use of the TRACE method.

    Note that sensitive data might be disclosed by the response.

    httpallowedurls: <none> Space-separated list of relative URLs (paths) rooted at "httpdocroot" (see below) to be served by httpd. If set, this option will limit served static content to only those paths specified (returning "404 Not Found" to any other client requested URLs). Otherwise, httpd will serve any content found in "httpdocroot".

    Note that any path specified by "rss_feedlist_template" is an exception to this rule.

    httpcontentmd5: 0 If enabled, HTTP responses will include a Content-MD5 header for the purpose of providing an end-to-end message integrity check (MIC) of the payload body. Note that enabling this option will use additional CPU to generate the MD5 digest, which may be ignored by clients anyways.

    httpdocroot: <none> If set, http will serve the static content (html/text/jpeg/gif files, etc) rooted at this directory. Otherwise, httpd will not serve any static content.

    httpkeepalive: 20s Set the length of the HTTP server's keepalive heartbeat. The default is 20 seconds. The minimum value is 0, which will disable the keepalive heartbeat. When enabled, if a request takes longer than httpkeepalive to process, the server will send the client provisional responses every httpkeepalive until the final response can be sent.

    For backward compatibility, if no unit is specified, seconds is assumed.

    httplogheaders: <none> Space-separated list of HTTP header fields that will be included in the requests logged by httpd(8).

    httpmodules: <empty string> Space-separated list of HTTP modules that will be enabled in httpd(8). This option has no effect on modules that are disabled at compile time due to missing dependencies (e.g. libical).

    Note that "domainkey" depends on "ischedule" being enabled, and that both "freebusy" and "ischedule" depend on "caldav" being enabled. Allowed values: admin, caldav, carddav, cgi, domainkey, freebusy, ischedule, jmap, prometheus, rss, tzdist, webdav

    httpprettytelemetry: 0 If enabled, HTTP response payloads including server-generated markup languages (HTML, XML) will utilize line breaks and indentation to promote better human-readability in telemetry logs. Note that enabling this option will increase the amount of data sent across the wire.

    httppts_uri: <none> The URL endpoint to use when for querying group membership, in URI Template (level 1) format [RFC 6570 <https://datatracker.ietf.org/doc/html/rfc6570.html>]. The URL MUST contain a variable called "groupId"

    httptimeout: 5m Set the length of the HTTP server's inactivity autologout timer. The minimum value is 0, which will disable persistent connections.

    For backwards compatibility, if no unit is specified, minutes is assumed.

    http_h2_altsvc: <none> If set, HTTP/2 (over TLS) will be advertised as being available on the specified [host]:port.

    http_jwt_key_dir: <none> The absolute path to a directory containing one or more key files to authenticate JSON Web Tokens (RFC 7519 <https://datatracker.ietf.org/doc/html/rfc7519.html>) for HTTP connections. Keys for the following JWS algorithms are supported: "HS256", "HS384", "HS512", "RS256", "RS384", "RS512".

    A key file consists of one or more keys encoded in PEM format. RSA keys must be embedded between the lines "-----BEGIN PUBLIC KEY-----" and "-----END PUBLIC KEY-----" HMAC digest keys must be embedded between the lines "-----BEGIN HMAC KEY-----" and "-----END HMAC KEY-----", encoded in base64. Any lines before or after a PEM key definition are ignored, empty lines are ignored anywhere in the file.

    The JSON Web Token must be the value of the HTTP "Authorization" header, using the "Bearer" authentication scheme. The JWS Header must include the "alg" and "typ" parameter. A header with any other parameter is rejected. The JWS Payload must include the "sub" claim with the Cyrus user identifier as value. It may include the "iat" claim (see http_jwt_max_age). A payload with any other claim is rejected.

    http_jwt_max_age: 0s Defines the timespan in which a JSON Web Token is valid (see http_jwt_key). The value must be zero or positive.

    If non-zero, the timespan starts at the point in time specified in the "iat" claim of the JWS Payload and ends after the duration of this option value has passed. Tokens without an "iat" claim, or with an issue date in the future, are rejected. There is no leeway for clock skew. Starting from Cyrus version 3.8, the "iat" claim only is validated if no "exp" claim is present.

    The zero value disables validation of the "iat" JWS claim.

    Starting from Cyrus 3.8, the "nbf" and "exp" claims always are validated.

    icalendar_max_size: 0 Maximum allowed iCalendar size. CalDAV and JMAP will reject storage of resources whose iCalendar representation is larger than this.

    If set to 0 (the default), a large internally-defined limit will be applied.

    If no unit is specified, bytes is assumed.

    idlesocket: {configdirectory}/socket/idle Unix domain socket that idled listens on.

    ignorereference: 0 For backwards compatibility with Cyrus 1.5.10 and earlier -- ignore the reference argument in LIST or LSUB commands.

    imapidlepoll: 60s The interval for polling for mailbox changes and ALERTs while running the IDLE command. This option is used when idled is not enabled or cannot be contacted. The minimum value is 1 second. A value of 0 will disable IDLE.

    For backward compatibility, if no unit is specified, seconds is assumed.

    imapidresponse: 1 If enabled, the server responds to an ID command with a parameter list containing: version, vendor, support-url, os, os-version, command, arguments, environment. Otherwise the server returns NIL.

    imapmagicplus: 0 Only list a restricted set of mailboxes via IMAP by using userid+namespace syntax as the authentication/authorization id. Using userid+ (with an empty namespace) will list only subscribed mailboxes.

    imap_inprogress_interval: 10s The interval after which the server will send an "INPROGRESS" response code to the client during a long-running imap command (e.g. search, copy). The default is 10 seconds. The minimum value is 0, which will disable "INPROGRESS" response codes.

    imipnotifier: <none> Notifyd(8) method to use for "IMIP" notifications which are based on the RFC 6047 <https://datatracker.ietf.org/doc/html/rfc6047.html>. If not set, "IMIP" notifications are disabled.

    implicit_owner_rights: lkxan The implicit Access Control List (ACL) for the owner of a mailbox.

    @include: <none> Directive which includes the specified file as part of the configuration. If the path to the file is not absolute, CYRUS_PATH is prepended.

    improved_mboxlist_sort: 0 Not used anymore.

    jmapaccess_url: <none> The JMAP Session URL to advertise to sucessfully authenticated IMAP clients, if the same credentials can be used to authenticate via JMAP (see draft-ietf-extra-jmapaccess).

    jmap_emailsearch_db_path: <none> The absolute path to the JMAP email search cache file. If not specified, JMAP Email/query and Email/queryChanges will not cache email search results.

    jmap_querycache_max_age: 0m The duration after which unused cached JMAP query results must be evicted from process memory. If non-zero, then the full result of the last query (before windowing) is stored in-memory. Subsequent queries with the same expression and query state can then page through the cached result. A zero value disables query result caching.

    If no unit is specified, minutes is assumed.

    This feature currently only is enabled for Email/query.

    jmap_preview_annot: <none> The name of the per-message annotation, if any, to store message previews.

    jmap_imagesize_annot: <none> The name of the per-message annotation, if any, that stores a JSON object, mapping message part numbers of MIME image types to an array of their image dimensions. The array must have at least two entries, where the first entry denotes the width and the second entry the height of the image. Any additional values are ignored.

    For example, if message part 1.2 contains an image of width 300 and height 200, then the value of this annotation would be:

    { "1.2" : [ 300, 200 ] }

    jmap_inlinedcids_annot: <none> The name of the per-message annotation, if any, that stores a JSON object, mapping RFC 2392 <https://datatracker.ietf.org/doc/html/rfc2392.html> Content-IDs referenced in HTML bodies to the respective HTML body part number.

    For example, if message part 1.2 contains HTML and references an inlined image at "<cid:foo>", then the value of this annotation would be:

    { "<foo>" : "1.2" }

    Note that the Content-ID key must be URL-unescaped and enclosed in angular brackets, as defined in RFC 2392 <https://datatracker.ietf.org/doc/html/rfc2392.html>.

    jmap_preview_length: 64B The maximum length of dynamically generated message previews. Previews stored in jmap_preview_annot take precedence.

    If no unit is specified, bytes is assumed.

    jmap_max_catenate_items: 100 The maximum number of items that can be catenated together by a JMAP Blob/upload action. Returned as the maxDataSources property value of the JMAP "<urn:ietf:params:jmap:blob>" capabilities object. Default value is 100.

    jmap_max_size_upload: 1G The maximum size that the JMAP API accepts for blob uploads. Returned as the maxSizeUpload property value of the JMAP "<urn:ietf:params:jmap:core>" capabilities object.

    For backward compatibility, if no unit is specified, kibibytes is assumed.

    jmap_max_size_blob_set: 4M The maximum size that the JMAP API accepts for Blob/upload. Returned as the maxSizeBlobSet property value of the JMAP "<urn:ietf:params:jmap:blob>" capabilities object.

    For backward compatibility, if no unit is specified, kibibytes is assumed.

    jmap_max_calendareventnotifs: 200 The maximum count of CalendarEventNotification objects to keep per account. Any notifications exceeding this count are expunged to make room for new ones. Zero or any negative number disables this limit.

    jmap_max_concurrent_upload: 5 The value to return for the maxConcurrentUpload property of the JMAP "<urn:ietf:params:jmap:core>" capabilities object. The Cyrus JMAP implementation does not enforce this rate-limit.

    jmap_max_size_request: 10M The maximum size that the JMAP API accepts for requests at the API endpoint. Returned as the maxSizeRequest property value of the JMAP "<urn:ietf:params:jmap:core>" capabilities object.

    For backward compatibility, if no unit is specified, kibibytes is assumed.

    jmap_max_concurrent_requests: 5 The value to return for the maxConcurrentRequests property of the JMAP "<urn:ietf:params:jmap:core>" capabilities object. The Cyrus JMAP implementation does not enforce this rate-limit.

    jmap_max_calls_in_request: 50 The maximum number of calls per JMAP request object. Returned as the maxCallsInRequest property value of the JMAP "<urn:ietf:params:jmap:core>" capabilities object.

    jmap_max_delayed_send: 512d The value to return for the maxDelayedSend property of the JMAP "<urn:ietf:params:jmap:emailsubmission>" capabilities object. The Cyrus JMAP implementation does not enforce this limit.

    For backward compatibility, if no unit is specified, seconds is assumed.

    jmap_max_objects_in_get: 4096 The maximum number of ids that a JMAP client may request in a single "/get" type method call. The actual number of returned objects in the response may exceed this number if the JMAP object type supports unbounded "/get" calls. Returned as the maxObjectsInGet property value of the JMAP "<urn:ietf:params:jmap:core>" capabilities object.

    jmap_max_objects_in_set: 4096 The maximum number of objects a JMAP client may send to create, update or destroy in a single /set type method call. Returned as the maxObjectsInSet property value of the JMAP "<urn:ietf:params:jmap:core>" capabilities object.

    jmap_mail_max_size_attachments_per_email: 10M The value to return for the maxSizeAttachmentsPerEmail property of the JMAP "<urn:ietf:params:jmap:mail>" capabilities object. The Cyrus JMAP implementation does not enforce this size limit.

    For backward compatibility, if no unit is specified, kibibytes is assumed.

    jmap_nonstandard_extensions: 0 If enabled, support non-standard JMAP extensions. If not enabled, only IETF standard JMAP functionality is supported.

    jmap_pushpoll: 60s The interval for polling for changes on an EventSource connection or when push has been ennabled on a WebSocket channel. The minimum value is 1 second. A value of 0 will disable push.

    If no unit is specified, seconds is assumed.

    jmap_set_has_attachment: 1 If enabled, the $hasAttachment flag is determined and set for new messages created with the JMAP Email/set or Email/import methods. This option should typically be enabled, but installations using Cyrus-external message annatotors to determine the $hasAttachment flag might want to disable it.

    jmap_vacation: 1 If enabled, support the JMAP vacation extension.

    jmapuploadfolder: #jmap The name of the folder for JMAP uploads.

    jmapsubmission_deleteonsend: 1 If enabled (the default) then delete the EmailSubmission as soon as the email * has been sent.

    jmapsubmissionfolder: #jmapsubmission The name of the folder for JMAP Submissions.

    jmappushsubscriptionfolder: #jmappushsubscription The name of the folder for JMAP Push Subscriptions.

    jmapnotificationfolder: #jmapnotification The name of the folder for JMAP notifications.

    iolog: 0 Should cyrus output I/O log entries.

    ldap_authz: <none> SASL authorization ID for the LDAP server.

    ldap_base: <empty string> Contains the LDAP base dn for the LDAP ptloader module.

    ldap_bind_dn: <none> Bind DN for the connection to the LDAP server (simple bind). Do not use for anonymous simple binds.

    ldap_deref: never Specify how aliases dereferencing is handled during search.

    Allowed values: search, find, always, never

    ldap_domain_base_dn: <empty string> Base DN to search for domain name spaces.

    ldap_domain_filter: (&(objectclass=domainrelatedobject)(associateddomain=%s)) Filter to use searching for domains.

    ldap_domain_name_attribute: associateddomain The attribute name for domains.

    ldap_domain_scope: sub Search scope

    Allowed values: sub, one, base

    ldap_domain_result_attribute: inetdomainbasedn Result attribute

    ldap_filter: (uid=%u) Specify a filter that searches user identifiers. The following tokens can be used in the filter string:

    %% = % %u = user %U = user portion of %u (%U = test when %u = <test@domain.tld>) %d = domain portion of %u if available (%d = domain.tld when %u = <test@domain.tld>), otherwise same as %R %R = domain portion of %u starting with @ (%R = @domain.tld when %u = <test@domain.tld>) %D = user dn. (use when ldap_member_method: filter) %1-9 = domain tokens (%1 = tld, %2 = domain when %d = domain.tld)

    ldap_filter is not used when ldap_sasl is enabled.

    ldap_group_base: <empty string> LDAP base dn for ldap_group_filter.

    ldap_groupmember_attribute: member Specify a field within groups with a list of members.

    ldap_group_filter: (cn=%u) Specify a filter that searches for group identifiers. See ldap_filter for more options.

    ldap_group_scope: sub Specify search scope for ldap_group_filter.

    Allowed values: sub, one, base

    ldap_id: <none> SASL authentication ID for the LDAP server

    ldap_mech: <none> SASL mechanism for LDAP authentication

    ldap_user_attribute: <none> Specify LDAP attribute to use as canonical user id.

    ldap_member_attribute: <none> See ldap_member_method.

    ldap_member_base: <empty string> LDAP base dn for ldap_member_filter.

    ldap_member_filter: (member=%D) Specify a filter for "ldap_member_method: filter". See ldap_filter for more options.

    ldap_member_method: attribute Specify a group method. The "attribute" method retrieves groups from a multi-valued attribute specified in ldap_member_attribute.

    The "filter" method uses a filter, specified by ldap_member_filter, to find groups; ldap_member_attribute is a single-value attribute group name. Allowed values: attribute, filter

    ldap_member_scope: sub Specify search scope for ldap_member_filter.

    Allowed values: sub, one, base

    ldap_password: <none> Password for the connection to the LDAP server (SASL and simple bind). Do not use for anonymous simple binds.

    ldap_realm: <none> SASL realm for LDAP authentication

    ldap_referrals: 0 Specify whether or not the client should follow referrals.

    ldap_restart: 1 Specify whether or not LDAP I/O operations are automatically restarted if they abort prematurely.

    ldap_sasl: 1 Use SASL for LDAP binds in the LDAP PTS module.

    ldap_sasl_authc: <none> Deprecated. Use ldap_id

    ldap_sasl_authz: <none> Deprecated. Use ldap_authz

    ldap_sasl_mech: <none> Deprecated. Use ldap_mech

    ldap_sasl_password: <none> Deprecated. User ldap_password

    ldap_sasl_realm: <none> Deprecated. Use ldap_realm

    ldap_scope: sub Specify search scope.

    Allowed values: sub, one, base

    ldap_servers: <ldap://localhost/> Deprecated. Use ldap_uri

    ldap_size_limit: 1 Specify a number of entries for a search request to return.

    ldap_start_tls: 0 Use transport layer security for <ldap://> using STARTTLS. Do not use ldaps:// in 'ldap_uri' with this option enabled.

    ldap_time_limit: 5s How long to wait for a search request to complete.

    For backward compatibility, if no unit is specified, seconds is assumed.

    ldap_timeout: 5s How long a search can take before timing out.

    For backward compatibility, if no unit is specified, seconds is assumed.

    ldap_ca_dir: <none> Path to a directory with CA (Certificate Authority) certificates.

    ldap_ca_file: <none> Path to a file containing CA (Certificate Authority) certificate(s).

    ldap_ciphers: <none> List of SSL/TLS ciphers to allow. The format of the string is described in ciphers(1).

    ldap_client_cert: <none> File containing the client certificate.

    ldap_client_key: <none> File containing the private client key.

    ldap_verify_peer: 0 Require and verify server certificate. If this option is yes, you must specify ldap_ca_file or ldap_ca_dir.

    ldap_tls_cacert_dir: <none> Deprecated in favor of ldap_ca_dir.

    ldap_tls_cacert_file: <none> Deprecated in favor of ldap_ca_file.

    ldap_tls_cert: <none> Deprecated in favor of ldap_client_cert.

    ldap_tls_key: <none> Deprecated in favor of ldap_client_key.

    ldap_tls_check_peer: 0 Deprecated in favor of ldap_verify_peer.

    ldap_tls_ciphers: <none> Deprecated in favor of ldap_ciphers.

    ldap_uri: <none> Contains a list of the URLs of all the LDAP servers when using the LDAP PTS module.

    ldap_version: 3 Specify the LDAP protocol version. If ldap_start_tls and/or ldap_use_sasl are enabled, ldap_version will be automatically set to 3.

    literalminus: 0 if enabled, CAPABILITIES will reply with LITERAL- rather than LITERAL+ (RFC 7888 <https://datatracker.ietf.org/doc/html/rfc7888.html>). Doesn't actually size-restrict uploads though.

    lmtp_downcase_rcpt: 1 If enabled, lmtpd will convert the recipient addresses to lowercase (up to a '+' character, if present).

    lmtp_exclude_specialuse: \Snoozed Don't allow delivery to folders with given special-use attributes.

    Note that "snoozing" of emails can currently only be done via the JMAP protocol, so delivery directly to the Snoozed mailbox is prohibited by default as it will not be moved back into INBOX automatically.

    lmtp_fuzzy_mailbox_match: 0 If enabled, and the mailbox specified in the detail part of the recipient (everything after the '+') does not exist, lmtpd will try to find the closest match (ignoring case, ignoring whitespace, falling back to parent) to the specified mailbox name.

    lmtp_over_quota_perm_failure: 0 If enabled, lmtpd returns a permanent failure code when a user's mailbox is over quota. By default, the failure is temporary, causing the MTA to queue the message and retry later.

    lmtp_preparse: 0 If enabled, lmtpd will map in the email and parse the xapian data for jmapsearch. The advantage is that the parsing is done without holding any locks. The disadvantage is that the parsing is done even if it winds up not being needed.

    lmtp_strict_quota: 0 If enabled, lmtpd returns a failure code when the incoming message will cause the user's mailbox to exceed its quota. By default, the failure won't occur until the mailbox is already over quota.

    lmtp_strict_rfc2821: 1 By default, lmtpd will be strict (per RFC 2821 <https://datatracker.ietf.org/doc/html/rfc2821.html>) with regards to which envelope addresses are allowed. If this option is set to false, 8bit characters in the local-part of envelope addresses are changed to 'X' instead. This is useful to avoid generating backscatter with certain MTAs like Postfix or Exim which accept such messages.

    lmtpsocket: {configdirectory}/socket/lmtp Unix domain socket that lmtpd listens on, used by deliver(8). This should match the path specified in cyrus.conf(5).

    lmtptxn_timeout: 5m Timeout used during a lmtp transaction to a remote backend (e.g. in a murder environment). Can be used to prevent hung lmtpds on proxy hosts when a backend server becomes unresponsive during a lmtp transaction. Change to zero for infinite.

    For backward compatibility, if no unit is specified, seconds is assumed.

    lock_debugtime: <none> A floating point number of seconds. If set, time how long we wait for any lock, and syslog the filename and time if it's longer than this value. The default of NULL means not to time locks. This is implemented for fcntl(2) locks and has no effect on flock(2) locks.

    loginrealms: <empty string> The list of remote realms whose users may authenticate using cross-realm authentication identifiers. Separate each realm name by a space. (A cross-realm identity is considered any identity returned by SASL with an "@" in it.).

    loginuseacl: 0 If enabled, any authentication identity which has a rights on a user's INBOX may log in as that user.

    logtimestamps: 0 Include notations in the protocol telemetry logs indicating the number of seconds since the last command or response.

    mailbox_default_options: 0 Default "options" field for the mailbox on create. You'll want to know what you're doing before setting this, but it can apply some default annotations like duplicate suppression.

    mailbox_initial_flags: <none> space-separated list of permanent flags which will be pre-set in every newly created mailbox. If you know you will require particular flag names then this avoids a possible race condition against a client that fills the entire 128 available slots. Default is NULL, which is no flags. Example: $Label1 $Label2 $Label3 NotSpam Spam

    mailbox_legacy_dirs: 0 If enabled, new mailboxes without parents will be created with legacy paths. sub mailboxes of users will still inherit the parent legacy setting.

    mailbox_maxmessages_addressbook: 0 Limit the number of messages that may exist in a single mailbox of "addressbook" type. Default (0) means no limit. This limit applies after quotas are checked, so if you have both quota limits and this set, then you will be denied if you are either over quota or over this per-mailbox count.

    mailbox_maxmessages_calendar: 0 Limit the number of messages that may exist in a single mailbox of "calendar" type. Default (0) means no limit. This limit applies after quotas are checked, so if you have both quota limits and this set, then you will be denied if you are either over quota or over this per-mailbox count.

    mailbox_maxmessages_email: 0 Limit the number of messages that may exist in a single mailbox of "email" (normal) type. Default (0) means no limit. This limit applies after quotas are checked, so if you have both quota limits and this set, then you will be denied if you are either over quota or over this per-mailbox count.

    mailnotifier: <none> Notifyd(8) method to use for "MAIL" notifications. If not set, "MAIL" notifications are disabled.

    master_bind_errors_fatal: 0 If enabled, failure to bind a port during startup is treated as a fatal error, causing master to shut down immediately. The default is to keep running, with the affected service disabled until the next SIGHUP causes it to retry.

    Note that this only applies during startup. New services that fail to come up in response to a reconfig+SIGHUP will just be logged and disabled like the default behaviour, without causing master to exit.

    master_pid_file: {configdirectory}/master.pid The path to a file that master(8) will write its PID to when running as a daemon.

    master_ready_file: {configdirectory}/master.ready The path to a file that master(8) will update to indicate that it is ready to accept client connections. This file will be created if it does not already exist, or truncated if it does.

    maxheaderlines: 1000 Maximum number of lines of header that will be processed into cache records. Default 1000. If set to zero, it is unlimited. If a message hits the limit, an error will be logged and the rest of the lines in the header will be skipped. This is to avoid malformed messages causing giant cache records.

    maxlogins_per_host: 0 Maximum number of logged in sessions allowed per service per host, zero means no limit.

    maxlogins_per_user: 0 Maximum number of logged in sessions allowed per service per user, zero means no limit.

    maxargssize: 0 Maximum total size of arguments to an IMAP command that will be accepted by Cyrus. Commands with arguments that exceed this limit will be rejected.

    If set to 0 (the default), a large internally-defined limit will be applied.

    If no unit is specified, bytes is assumed.

    maxmessagesize: 0 Maximum size of messages that will be accepted by Cyrus. This affects LMTP deliveries, IMAP appends, DAV uploads, etc. Messages larger than this will be rejected.

    If set to 0 (the default), a large internally-defined limit will be applied.

    If no unit is specified, bytes is assumed.

    maxliteral: 128K Maximum size of a single literal allowed by the IMAP parser.

    If set to 0, a large internally-defined limit will be applied.

    If no unit is specified, bytes is assumed.

    Literals used for message [part] data in APPEND are only limited by the 'maxmessagesize' option.

    If the 'literalminus' option is enabled, non-synchonizing literals will be limited to the lesser of 4K and either 'maxliteral' or 'maxmessagesize', depending on the use-case.

    maxquoted: 128K Maximum size of a single quoted string allowed by the IMAP parser.

    If set to 0, a large internally-defined limit will be applied.

    If no unit is specified, bytes is assumed.

    maxword: 128K Maximum size of a single word allowed by the IMAP parser.

    If set to 0, a large internally-defined limit will be applied.

    If no unit is specified, bytes is assumed.

    mboxkey_db: twoskip The cyrusdb backend to use for mailbox keys.

    Allowed values: skiplist, twoskip, zeroskip

    mboxlist_db: twoskip The cyrusdb backend to use for the mailbox list.

    Allowed values: flat, skiplist, sql, twoskip, zeroskip

    mboxlist_db_path: <none> The absolute path to the mailboxes db file. If not specified will be configdirectory/mailboxes.db

    mboxname_lockpath: <none> Path to mailbox name lock files (default $conf/lock)

    metapartition_files: <empty string> Space-separated list of metadata files to be stored on a metapartition rather than in the mailbox directory on a spool partition. Allowed values: header, index, cache, expunge, squat, annotations, lock, dav, archivecache

    metapartition-name: <none> The pathname of the metadata partition name, corresponding to spool partition partition-name. For any mailbox residing in a directory on partition-name, the metadata files listed in metapartition_files will be stored in a corresponding directory on metapartition-name. Note that not every partition-name option is required to have a corresponding metapartition-name option, so that you can selectively choose which spool partitions will have separate metadata partitions.

    mupdate_authname: <none> The SASL username (Authentication Name) to use when authenticating to the mupdate server (if needed).

    mupdate_config: standard The configuration of the mupdate servers in the Cyrus Murder. The "standard" config is one in which there are discreet frontend (proxy) and backend servers. The "unified" config is one in which a server can be both a frontend and backend. The "replicated" config is one in which multiple backend servers all share the same mailspool, but each have their own "replicated" copy of mailboxes.db. Allowed values: standard, unified, replicated

    munge8bit: 1 If enabled, lmtpd munges messages with 8-bit characters in the headers. The 8-bit characters are changed to `X'. If reject8bit is enabled, setting munge8bit has no effect. (A proper solution to non-ASCII characters in headers is offered by RFC 2047 <https://datatracker.ietf.org/doc/html/rfc2047.html> and its predecessors.)

    mupdate_connections_max: 128 The max number of connections that a mupdate process will allow, this is related to the number of file descriptors in the mupdate process. Beyond this number connections will be immediately issued a BYE response.

    mupdate_password: <none> The SASL password (if needed) to use when authenticating to the mupdate server.

    mupdate_port: 3905 The port of the mupdate server for the Cyrus Murder.

    mupdate_realm: <none> The SASL realm (if needed) to use when authenticating to the mupdate server.

    mupdate_retry_delay: 20 The base time to wait between connection retries to the mupdate server.

    mupdate_server: <none> The mupdate server for the Cyrus Murder.

    mupdate_username: <empty string> The SASL username (Authorization Name) to use when authenticating to the mupdate server.

    mupdate_workers_max: 50 The maximum number of mupdate worker threads (overall).

    mupdate_workers_maxspare: 10 The maximum number of idle mupdate worker threads.

    mupdate_workers_minspare: 2 The minimum number of idle mupdate worker threads.

    mupdate_workers_start: 5 The number of mupdate worker threads to start.

    netscapeurl: <none> If enabled at compile time, this specifies a URL to reply when Netscape asks the server where the mail administration HTTP server is. Administrators should set this to a local resource.

    newsaddheaders: to Space-separated list of headers to be added to incoming usenet articles. Added To: headers will contain email delivery addresses corresponding to each newsgroup in the Newsgroups: header. Added Reply-To: headers will contain email delivery addresses corresponding to each newsgroup in the Followup-To: or Newsgroups: header. If the specified header(s) already exist in an article, the email delivery addresses will be appended to the original header body(s).

    This option applies if and only if the newspostuser option is set. Allowed values: to, replyto

    newsgroups: * A wildmat pattern specifying which mailbox hierarchies should be treated as newsgroups. Only mailboxes matching the wildmat will accept and/or serve articles via NNTP. If not set, a default wildmat of "*" (ALL shared mailboxes) will be used. If the newsprefix option is also set, the default wildmat will be translated to "<newsprefix>.*"

    newsmaster: news Userid that is used for checking access controls when executing Usenet control messages. For instance, to allow articles to be automatically deleted by cancel messages, give the "news" user the 'd' right on the desired mailboxes. To allow newsgroups to be automatically created, deleted and renamed by the corresponding control messages, give the "news" user the 'c' right on the desired mailbox hierarchies.

    newspeer: <none> A list of whitespace-separated news server specifications to which articles should be fed. Each server specification is a string of the form [user[:pass]@]host[:port][/wildmat] where 'host' is the fully qualified hostname of the server, 'port' is the port on which the server is listening, 'user' and 'pass' are the authentication credentials and 'wildmat' is a pattern that specifies which groups should be fed. If no 'port' is specified, port 119 is used. If no 'wildmat' is specified, all groups are fed. If 'user' is specified (even if empty), then the NNTP POST command will be used to feed the article to the server, otherwise the IHAVE command will be used.

    A '@' may be used in place of '!' in the wildmat to prevent feeding articles cross-posted to the given group, otherwise cross-posted articles are fed if any part of the wildmat matches. For example, the string "peer.example.com:*,!control.*,@local.*" would feed all groups except control messages and local groups to peer.example.com. In the case of cross-posting to local groups, these articles would not be fed.

    newspostuser: <none> Userid used to deliver usenet articles to newsgroup folders (usually via lmtp2nntp). For example, if set to "post", email sent to "post+comp.mail.imap" would be delivered to the "comp.mail.imap" folder.

    When set, the Cyrus NNTP server will add the header(s) specified in the newsaddheaders option to each incoming usenet article. The added header(s) will contain email delivery addresses corresponding to each relevant newsgroup. If not set, no headers are added to usenet articles.

    newsprefix: <none> Prefix to be prepended to newsgroup names to make the corresponding IMAP mailbox names.

    newsrc_db_path: <none> The absolute path to the newsrc db file. If not specified, will be configdirectory/fetchnews.db

    nntptimeout: 3m Set the length of the NNTP server's inactivity autologout timer. The minimum value is 3 minutes, also the default.

    For backward compatibility, if no unit is specified, minutes is assumed.

    notesmailbox: <none> The top level mailbox in each user's account which is used to store * Apple-style Notes. Default is blank (disabled).

    notifysocket: {configdirectory}/socket/notify Unix domain socket that the mail notification daemon listens on.

    notify_external: <none> Path to the external program that notifyd(8) will call to send mail notifications.

    The external program will be called with the following command line options:

-c class

-p priority

-u user

-m mailbox

    And the notification message will be available on stdin.

    partition-name: <none> The pathname of the partition name. At least one partition pathname MUST be specified. If the defaultpartition option is used, then its pathname MUST be specified. For example, if the value of the defaultpartion option is part1, then the partition-part1 field is required.

    partition_select_mode: freespace-most Partition selection mode.

random
    (pseudo-)random selection

freespace-most
    partition with the most free space (KiB)

freespace-percent-most
    partition with the most free space (%)

freespace-percent-weighted
    each partition is weighted according to its free space (%); the more free space the partition has, the more chances it has to be selected

freespace-percent-weighted-delta
    each partition is weighted according to its difference of free space (%) compared to the most used partition; the more the partition is lagging behind the most used partition, the more chances it has to be selected

    Note that actually even the most used partition has a few chances to be selected, and those chances increase when other partitions get closer

    Allowed values: random, freespace-most, freespace-percent-most, freespace-percent-weighted, freespace-percent-weighted-delta

    partition_select_exclude: <none> List of partitions to exclude from selection mode.

    partition_select_usage_reinit: 0 For a given session, number of operations (e.g. partition selection) for which partitions usage data are cached.

    partition_select_soft_usage_limit: 0 Limit of partition usage (%): if a partition is over that limit, it is automatically excluded from selection mode.

    If all partitions are over that limit, this feature is not used anymore.

    plaintextloginpause: <none> Time to pause after a successful plaintext login. For systems that support strong authentication, this permits users to perceive a cost of using plaintext passwords. (This does not affect the use of PLAIN in SASL authentications.)

    For backward compatibility, if no unit is specified, seconds is assumed.

    plaintextloginalert: <none> Message to send to client after a successful plaintext login.

    popexpiretime: -1 The duration advertised as being the minimum a message may be left on the POP server before it is deleted (via the CAPA command, defined in the POP3 Extension Mechanism, which some clients may support). This duration has a granularity of whole days, with partial days truncated (so e.g. "45m" is effectively "0d"). "NEVER", the default, may be specified with a negative number.

    The Cyrus POP3 server never deletes mail, no matter what the value of this parameter is. However, if a site implements a less liberal policy, it needs to change this parameter accordingly.

    For backward compatibility, if no unit is specified, days is assumed.

    popminpoll: <none> Set the minimum amount of time the server forces users to wait between successive POP logins.

    For backward compatibility, if no unit is specified, minutes is assumed.

    popsubfolders: 0 Allow access to subfolders of INBOX via POP3 by using userid+subfolder syntax as the authentication/authorization id.

    poppollpadding: 1 Create a softer minimum poll restriction. Allows poppollpadding connections before the minpoll restriction is triggered. Additionally, one padding entry is recovered every popminpoll minutes. This allows for the occasional polling rate faster than popminpoll, (i.e., for clients that require a send/receive to send mail) but still enforces the rate long-term. Default is 1 (disabled).

    The easiest way to think of it is a queue of past connections, with one slot being filled for every connection, and one slot being cleared every popminpoll minutes. When the queue is full, the user will not be able to check mail again until a slot is cleared. If the user waits a sufficient amount of time, they will get back many or all of the slots.

    poptimeout: 10m Set the length of the POP server's inactivity autologout timer. The minimum value is 10 minutes, the default.

    For backward compatibility, if no unit is specified, minutes is assumed.

    popuseacl: 0 Enforce IMAP ACLs in the pop server. Due to the nature of the POP3 protocol, the only rights which are used by the pop server are 'r', 't', and 's' for the owner of the mailbox. The 'r' right allows the user to open the mailbox and list/retrieve messages. The 't' right allows the user to delete messages. The 's' right allows messages retrieved by the user to have the \Seen flag set (only if popuseimapflags is also enabled).

    popuseimapflags: 0 If enabled, the pop server will set and obey IMAP flags. Messages having the \Deleted flag are ignored as if they do not exist. Messages that are retrieved by the client will have the \Seen flag set. All messages will have the \Recent flag unset.

    postmaster: postmaster Username that is used as the 'From' address in rejection MDNs produced by sieve.

    postuser: <empty string> Userid used to deliver messages to shared folders. For example, if set to "bb", email sent to "bb+shared.blah" would be delivered to the "shared.blah" folder. By default, an email address of "+shared.blah" would be used.

    proc_path: <none> Path to proc directory. Default is NULL - must be an absolute path if specified. If not specified, the path $configdirectory/proc/ will be used.

    prometheus_enabled: 0 Whether tracking of metrics for Prometheus is enabled.

    prometheus_need_auth: admin Authentication level required to fetch Prometheus metrics.

    Allowed values: none, user, admin

    prometheus_update_freq: 10s Deprecated in favour of prometheus_service_update_freq, prometheus_master_update_freq, and prometheus_usage_update_freq.

    prometheus_service_update_freq: 10s Frequency in at which promstatsd should re-collate its service statistics report. The minimum value is 1 second.

    If no unit is specified, seconds is assumed.

    prometheus_master_update_freq: <none> Frequency in at which master should re-collate its statistics report. If not set, prometheus_service_update_freq is used.

    If no unit is specified, seconds is assumed.

    prometheus_usage_update_freq: <none> Frequency in at which promstatsd should re-collate its usage statistics report. Note that this report is relatively expensive to produce. If not set, usage statistics are not reported.

    Best to make this a multiple of prometheus_service_update_freq.

    If no unit is specified, seconds is assumed.

    prometheus_stats_dir: <none> Directory to use for gathering prometheus statistics. If specified, must be an absolute path. If not specified, the default path $configdirectory/stats/ will be used. It may be advantageous to locate this directory on ephemeral storage.

    proxy_authname: proxy The authentication name to use when authenticating to a backend server in the Cyrus Murder.

    proxy_compress: 0 Try to enable protocol-specific compression when performing a client connection to a backend server in the Cyrus Murder.

    Note that this should only be necessary over slow network connections. Also note that currently only IMAP and MUPDATE support compression.

    proxy_password: <none> The default password to use when authenticating to a backend server in the Cyrus Murder. May be overridden on a host-specific basis using the hostname_password option.

    proxy_realm: <none> The authentication realm to use when authenticating to a backend server in the Cyrus Murder

    proxyd_allow_status_referral: 0 Set to true to allow proxyd to issue referrals to clients that support it when answering the STATUS command. This is disabled by default since some clients issue many STATUS commands in a row, and do not cache the connections that these referrals would cause, thus resulting in a higher authentication load on the respective backend server.

    proxyd_disable_mailbox_referrals: 0 Set to true to disable the use of mailbox-referrals on the proxy servers.

    proxyservers: <none> A list of users and groups that are allowed to proxy for other users, separated by spaces. Any user listed in this will be allowed to login for any other user: use with caution. In a standard murder this option should ONLY be set on backends. DO NOT SET on frontends or things won't work properly.

    pts_module: afskrb The PTS module to use.

    Allowed values: afskrb, ldap, http

    ptloader_sock: <none> Unix domain socket that ptloader listens on. (defaults to configdirectory/ptclient/ptsock).

    ptscache_db: twoskip The cyrusdb backend to use for the pts cache.

    Allowed values: skiplist, twoskip, zeroskip

    ptscache_db_path: <none> The absolute path to the ptscache db file. If not specified, will be configdirectory/ptscache.db

    ptscache_timeout: 3h The timeout for the PTS cache database when using the auth_krb_pts authorization method (default: 3 hours).

    For backward compatibility, if no unit is specified, seconds is assumed.

    ptskrb5_convert524: 1 When using the AFSKRB ptloader module with Kerberos 5 canonicalization, do the final 524 conversion to get a n AFS style name (using '.' instead of '/', and using short names.

    ptskrb5_strip_default_realm: 1 When using the AFSKRB ptloader module with Kerberos 5 canonicalization, strip the default realm from the userid (this does not affect the stripping of realms specified by the afspts_localrealms option).

    qosmarking: cs0 This specifies the Class Selector or Differentiated Services Code Point designation on IP headers (in the ToS field). Allowed values: cs0, cs1, cs2, cs3, cs4, cs5, cs6, cs7, af11, af12, af13, af21, af22, af23, af31, af32, af33, af41, af42, af43, ef

    quota_db: quotalegacy The cyrusdb backend to use for quotas.

    Allowed values: flat, skiplist, sql, quotalegacy, twoskip, zeroskip

    quota_db_path: <none> The absolute path for the quota database (if you choose a single-file quota DB type - or the base path if you choose quotalegacy). If not specified will be configdirectory/quotas.db or configdirectory/quota/

    quota_use_conversations: 0 If conversations it enabled and quotaroot is a user folder, use the conversations quota counts, which count multiple copies of exactly the same message (by GUID) as only one.

    quotawarn: 90 Deprecated in favour of quotawarnpercent.

    quotawarnpercent: 90 The percent of quota utilization over which the server generates warnings.

    quotawarnkb: <none> Deprecated in favour of quotawarnsize.

    quotawarnsize: 0 The maximum amount of free space at which to give a quota warning (if this value is 0, or if the quota is smaller than this amount, then warnings are always given).

    Note that quota has kibibyte granularity. Values specified here will be truncated to the nearest whole kibibyte.

    For backward compatibility, if no unit is specified, kibibytes is assumed.

    quotawarnmsg: 0 The maximum amount of messages at which to give a quota warning (if this value is 0, or if the quota is smaller than this amount, then warnings are always given).

    readonly: 0 If enabled, all IMAP, POP and JMAP connections are read-only, * no writes allowed.

    replicaonly: 0 If enabled, marks the server as only being a replica. This will * stop calalarmd from doing anything, and also deny any non-silent * writes (nothing is allowed to increase modseq or uidvalidity).

    reject8bit: 0 If enabled, lmtpd rejects messages with 8-bit characters in the headers.

    restore_authname: <none> The authentication used by the restore tool when authenticating to an IMAP/sync server.

    restore_password: <none> The password used by the restore tool when authenticating to an IMAP/sync server.

    restore_realm: <none> The authentication realm used by the restore tool when authenticating to an IMAP/sync server.

    reverseacls: 0 At startup time, ctl_cyrusdb -r will check this value and it will either add or remove reverse ACL pointers from mailboxes.db

    reverseuniqueids: 1 Deprecated. No longer used.

    rfc2046_strict: 0 If enabled, imapd will be strict (per RFC 2046 <https://datatracker.ietf.org/doc/html/rfc2046.html>) when matching MIME boundary strings. This means that boundaries containing other boundaries as substrings will be treated as identical. Since enabling this option will break some messages created by Eudora 5.1 (and earlier), it is recommended that it be left disabled unless there is good reason to do otherwise.

    rfc2047_utf8: 0 If enabled, imapd will parse any non-encoded character sequence in MIME header values as UTF8. This is useful for installations that either advertise the UTF8SMTP (RFC 5335 <https://datatracker.ietf.org/doc/html/rfc5335.html>) extension or receive mails with improperly escaped UTF-8 byte sequences. It is recommended that this option is left disabled unless there is good reason to do otherwise.

    rfc3028_strict: 1 If enabled, Sieve will be strict (per RFC 3028 <https://datatracker.ietf.org/doc/html/rfc3028.html>) with regards to which headers are allowed to be used in address and envelope tests. This means that only those headers which are defined to contain addresses will be allowed in address tests and only "to" and "from" will be allowed in envelope tests. When disabled, ANY grammatically correct header will be allowed.

    rss_feedlist_template: <none> File containing HTML that will be used as a template for displaying the list of available RSS feeds. A single instance of the variable %RSS_FEEDLIST% should appear in the file, which will be replaced by a nested unordered list of feeds. The toplevel unordered list will be tagged with an id of "feed" (<ul id='feed'>) which can be used by stylesheet(s) in your template. The dynamically created list of feeds based on the HTML template will be accessible at the "/rss" URL on the server.

    rss_feeds: * A wildmat pattern specifying which mailbox hierarchies should be treated as RSS feeds. Only mailboxes matching the wildmat will have their messages available via RSS. If not set, a default wildmat of "*" (ALL mailboxes) will be used.

    rss_maxage: <none> Maximum age of items to display in an RSS channel. If non-zero, httpd will only display items received within this time period. If set to 0, all available items will be displayed (the default).

    For backward compatibility, if no unit is specified, days is assumed.

    rss_maxitems: 0 Maximum number of items to display in an RSS channel. If non-zero, httpd will display no more than the rss_maxitems most recent items. If set to 0, all available items will be displayed (the default).

    rss_maxsynopsis: 0 Maximum RSS item synopsis length. If non-zero, httpd will display no more than the first rss_maxsynopsis characters of an item's synopsis. If set to 0, the entire synopsis will be displayed (the default).

    rss_realm: <none> The realm to present for HTTP authentication of RSS feeds. If not set (the default), the value of the "servername" option will be used.

    sasl_auto_transition: 0 If enabled, the SASL library will automatically create authentication secrets when given a plaintext password. See the SASL documentation.

    sasl_maximum_layer: 256 Maximum SSF (security strength factor) that the server will allow a client to negotiate.

    sasl_minimum_layer: 0 The minimum SSF that the server will allow a client to negotiate. A value of 1 requires integrity protection; any higher value requires some amount of encryption.

    sasl_option: 0 Any SASL option can be set by preceding it with sasl_. This file overrides the SASL configuration file.

    sasl_pwcheck_method: <none> The mechanism used by the server to verify plaintext passwords. Possible values include "auxprop", "saslauthd", and "pwcheck".

    search_batchsize: 20 The number of messages to be indexed in one batch (default 20). Note that long batches may delay user commands or mail delivery.

    search_attachment_extractor_url: <none> A HTTP or HTTPS URL to extract search text from rich text attachments and other media during search indexing. The server at this URL must implement the following protocol:

    1. For each attachment of an email, Cyrus sends a GET request to the URL <extractor-url>/<cyrus-id>, where <extractor-url> is the configured URL and <cyrus-id> is a Cyrus-chosen path segment that uniquely identifies this attachment.

    2. If the extractor already has a cached plain text extract of the attachment identified by <cyrus-id> then it may return HTTP status code 200 (OK) and the plain text extract with a Content-Type "text/plain" header. Otherwise it must return HTTP status 404 (Not Found).

    3. If Cyrus receives the HTTP status code 404 (Not Found), then it sends a PUT request to the same URL as previously. The PUT request body contains the decoded, binary body of the attachment. The Content-Type request header has the same value as declared in the MIME part headers, including any type parameters.

    4. The extractor must return the plain text extract with either HTTP status 200 (OK) or 201 (Created) and a Content-Type "text/plain" header. If no text can be extracted, then the extractor may return any return code in the range 4xx, or 200 and an empty response body.

    Any other HTTP status code is treated as an error. For performance reasons, the Cyrus indexer attempts to keep-alive the TCP connection to the extractor. Xapian only.

    search_attachment_extractor_request_timeout: 5m Defines the duration after which to cancel non-responding requests to the search attachment extractor service.

    If no unit is specified, seconds is assumed.

    search_attachment_extractor_idle_timeout: 5m Defines the duration after which to close unused connections to the search attachment extractor service. If the idle timeout is less than search_attachment_extractor_request_timeout, then it is ignored and request timeout used instead.

    If no unit is specified, seconds is assumed.

    search_index_language: 0 If enabled, then messages bodies are stemmed by detected language in addition to the default English stemmer. Xapian only.

    search_index_parts: 0 Deprecated. No longer used.

    search_index_skip_domains: <none> A space separated list of domains - if set, any users in the listed domains will be skipped when indexing.

    search_index_skip_users: <none> A space separated list of usernames - if set, any users in the list will be skipped when indexing.

    search_query_language: 0 Deprecated. No longer used.

    search_normalisation_max: 1000 A resource bound for the combinatorial explosion of search expression tree complexity caused by normalising expressions with many OR nodes. These can use more CPU time to optimise than they save IO time in scanning folders.

    search_engine: none The indexing engine used to speed up searching.

    Allowed values: none, squat, xapian

    search_fuzzy_always: 0 Whether to enable RFC 6203 <https://datatracker.ietf.org/doc/html/rfc6203.html> FUZZY search for all IMAP SEARCH. If turned on, search attributes will be searched using FUZZY search by default. If turned off, clients have to explicitly use the FUZZY search key to enable fuzzy search for regular SEARCH commands.

    search_index_headers: 1 Whether to index headers other than From, To, Cc, Bcc, and Subject. Experiment shows that some headers such as Received and DKIM-Signature can contribute up to 2/3rds of the index size but almost nothing to the utility of searching. Note that if header indexing is disabled, headers can still be searched, the searches will just be slower.

    search_indexed_db: twoskip The cyrusdb backend to use for the search latest indexed uid state. Xapian only.

    Allowed values: flat, skiplist, twoskip, zeroskip

    search_maxtime: <none> The maximum number of seconds to run a search for before aborting. Default of no value means search "forever" until other timeouts.

    search_maxsize: 4M The maximum size to index for each message part. Message contents that occur after this byte offset will not be indexed nor used to generate search snippets. Xapian-only.

    For backward compatibility, if no unit is specified, kibibytes is assumed.

    search_queryscan: 5000 The minimum number of records require to do a direct scan of all G keys * rather than indexed lookups. A value of 0 means always do indexed lookups.

    search_skipdiacrit: 1 When searching, should diacriticals be stripped from the search terms. The default is "true", a search for "hav" will match "Håvard". This is not RFC 5051 <https://datatracker.ietf.org/doc/html/rfc5051.html> compliant, but is backwards compatible, and may be preferred by some sites.

    search_skiphtml: 0 If enabled, HTML parts of messages are skipped, i.e. not indexed and not searchable. Otherwise, they're indexed.

    search_whitespace: merge When searching, how whitespace should be handled. Options are: "skip" (default in 2.3 and earlier series) - where a search for "equi" would match "the quick brown fox". "merge" - the default, where "he qu" would match "the quick brownfox", and "keep", where whitespace must match exactly. The default of "merge" is recommended for most cases - it's a good compromise which keeps words separate. Allowed values: skip, merge, keep

    search_snippet_length: 255 The maximum byte length of a snippet generated by the XSNIPPETS command. Only supported by the Xapian search backend, which attempts to always fill search_snippet_length bytes in the generated snippet.

    search_stopword_path: <none> The absolute base path to the search stopword lists. If not specified, no stopwords will be taken into account during search indexing. Currently, the only supported and default stop word file is english.txt.

    searchpartition-name: <none> The pathname where to store the xapian search indexes of searchtier for mailboxes of partition name. This must be configured for the defaultsearchtier and any additional search tier (see squatter for details).

    For example: if defaultpartition is defined as part1 and defaultsearchtier as tier1 then the configuration must contain an entry tier1searchpartition-part1 that defines the path where to store this tier1's search index for the part1 partition.

    This option MUST be specified for xapian search.

    seenstate_db: twoskip The cyrusdb backend to use for the seen state.

    Allowed values: flat, skiplist, twoskip, zeroskip

    sendmail: /usr/lib/sendmail The pathname of the sendmail executable. Sieve invokes sendmail for sending rejections, redirects and vacation responses.

    sendmail_auth_id: CYRUS_SENDMAIL_AUTH_ID The name of an environment variable to set when invoking sendmail. The value of this environment variable will contain the user id of the currently authenticated user. If no user is authenticated the environment variable is not set.

    serverlist: <none> Whitespace separated list of backend server names. Used for finding server with the most available free space for proxying CREATE.

    serverlist_select_mode: freespace-most Server selection mode.

random
    (pseudo-)random selection

freespace-most
    backend with the most (total) free space (KiB)

freespace-percent-most
    backend whose partition has the most free space (%)

freespace-percent-weighted
    same as for partition selection, comparing the free space (%) of the least used partition of each backend

freespace-percent-weighted-delta
    same as for partition selection, comparing the free space (%) of the least used partition of each backend.

    Allowed values: random, freespace-most, freespace-percent-most, freespace-percent-weighted, freespace-percent-weighted-delta

    serverlist_select_usage_reinit: 0 For a given session, number of operations (e.g. backend selection) for which backend usage data are cached.

    serverlist_select_soft_usage_limit: 0 Limit of backend usage (%): if a backend is over that limit, it is automatically excluded from selection mode.

    If all backends are over that limit, this feature is not used anymore.

    servername: <none> This is the hostname visible in the greeting messages of the POP, IMAP and LMTP daemons. If it is unset, then the result returned from gethostname(2) is used. This is also the value used by murder clusters to identify the host name. It should be resolvable by DNS to the correct host, and unique within an active cluster. If you are using low level replication (e.g. drbd) then it should be the same on each copy and the DNS name should also be moved to the new master on failover.

    serverinfo: on The server information to display in the greeting and capability responses. Information is displayed as follows: "off" = no server information in the greeting or capabilities

    "min" = servername in the greeting; no server information in the capabilities

    "on" = servername and product version in the greeting; product version in the capabilities

    Allowed values: off, min, on

    sharedprefix: Shared Folders If using the alternate IMAP namespace, the prefix for the shared namespace. The hierarchy delimiter will be automatically appended.

    sieve_allowreferrals: 1 If enabled, timsieved will issue referrals to clients when the user's scripts reside on a remote server (in a Murder). Otherwise, timsieved will proxy traffic to the remote server.

    sieve_duplicate_max_expiration: 90d Maximum expiration time for duplicate message tracking records.

    For backward compatibility, if no unit is specified, seconds is assumed.

    sieve_extensions: fileinto reject vacation vacation-seconds notify include envelope environment body relational regex subaddress copy date index imap4flags mailbox mboxmetadata servermetadata variables editheader extlists duplicate ihave fcc special-use redirect-dsn redirect-deliverby mailboxid vnd.cyrus.log vnd.cyrus.jmapquery processcalendar snooze vnd.cyrus.implicit_keep_target Space-separated list of Sieve extensions allowed to be used in sieve scripts, enforced at submission by timsieved(8). Any previously installed script will be unaffected by this option and will continue to execute regardless of the extensions used. This option has no effect on options that are disabled at compile time (e.g., "regex"). Allowed values: fileinto, reject, vacation, vacation-seconds, notify, include, envelope, environment, body, relational, regex, subaddress, copy, date, index, imap4flags=imapflags, mailbox, mboxmetadata, servermetadata, variables, editheader, extlists, duplicate, ihave, fcc, special-use, redirect-dsn, redirect-deliverby, mailboxid, vnd.cyrus.log=x-cyrus-log, vnd.cyrus.jmapquery=x-cyrus-jmapquery, processcalendar=vnd.cyrus.imip, snooze=vnd.cyrus.snooze=x-cyrus-snooze, vnd.cyrus.implicit_keep_target

    sieve_folder: #sieve The name of the folder for storing Sieve scripts.

    sieve_maxscriptsize: 32K Maximum size any sieve script can be, enforced at submission by timsieved(8) and JMAP.

    For backward compatibility, if no unit is specified, kibibytes is assumed.

    sieve_maxscripts: 5 Maximum number of sieve scripts any user may have, enforced at submission by timsieved(8).

    sieve_utf8fileinto: 0 If enabled, the sieve engine expects folder names for the fileinto action in scripts to use UTF8 encoding. Otherwise, modified UTF7 encoding should be used.

    sieve_sasl_send_unsolicited_capability: 1 Deprecated: this option does nothing.

    sieve_use_lmtp_reject: 1 Enabled by default. If reject can be done via LMTP, then return a 550 rather than generating the bounce message in Cyrus.

    sieve_vacation_min_response: 3d Minimum time interval between consecutive vacation responses, per RFC 6131 <https://datatracker.ietf.org/doc/html/rfc6131.html>. The default is 3 days.

    For backward compatibility, if no unit is specified, seconds is assumed.

    sieve_vacation_max_response: 90d Maximum time interval between consecutive vacation responses, per RFC 6131 <https://datatracker.ietf.org/doc/html/rfc6131.html>. The default is 90 days. The minimum is 7 days.

    For backward compatibility, if no unit is specified, seconds is assumed.

    sievedir: /usr/sieve If sieveusehomedir is false, this directory is searched for Sieve scripts.

    sievenotifier: <none> Notifyd(8) method to use for "SIEVE" notifications. If not set, "SIEVE" notifications are disabled.

    This method is only used when no method is specified in the script.

    sieveusehomedir: 0 If enabled, lmtpd will look for Sieve scripts in user's home directories: ~user/.sieve.

    anysievefolder: 0 It must be "yes" in order to permit the autocreation of any INBOX subfolder requested by a sieve filter, through the "fileinto" action.

    singleinstancestore: 1 If enabled, imapd, lmtpd and nntpd attempt to only write one copy of a message per partition and create hard links, resulting in a potentially large disk savings.

    skiplist_always_checkpoint: 1 If enabled, this option forces the skiplist cyrusdb backend to always checkpoint when doing a recovery. This causes slightly more IO, but on the other hand leads to more efficient databases, and the entire file is already "hot".

    skiplist_unsafe: 0 If enabled, this option forces the skiplist cyrusdb backend to not sync writes to the disk. Enabling this option is NOT RECOMMENDED.

    smtp_backend: sendmail The SMTP backend to use for sending email.

    The "host" backend sends message submissions via a TCP socket to the SMTP host defined in the config option smtp_host.

    The "sendmail" backend forks the Cyrus process into the executable defined in the config option sendmail. The executable must accept "-bs" as command line argument, read from stdin and must implement the minimum SMTP protocol as defined in section 4.5.1 of RFC 5321 <https://datatracker.ietf.org/doc/html/rfc5321.html>.

    If the SMTP EHLO command reports AUTH (RFC 4954 <https://datatracker.ietf.org/doc/html/rfc4954.html>) as a supported extension, then the MAIL FROM command includes the AUTH parameter, with its value set to the name of any authenticated user which triggered the email. The AUTH parameter is omitted if the user is unknown to the calling process.

    If the directory configdirectory/log/smtpclient.smtp_backend exists, then telemetry logs for outgoing SMTP sessions will be created in this directory.

    Allowed values: host, sendmail

    smtp_host: localhost:587 The SMTP host to use for sending mail (also see the smtp_backend option). The value of this option must the name or IP address of a TCP host, followed optionally by a colon and the port or service to use. The default port is 587. TLS may be activated by appending "/tls" to the value. Authentication is enabled if smtp_auth_authname is set. Authentication can be explicitly disabled by appending "/noauth" to the host address.

    smtp_auth_authname: <none> The authentication name to use when authenticating to the SMTP server defined in smtp_host.

    smtp_auth_password: <none> The password to use when authenticating to the SMTP server defined in smtp_host.

    smtp_auth_realm: <none> The authentication SASL realm to use when authenticating to a SMTP server.

    soft_noauth: 1 If enabled, lmtpd returns temporary failures if the client does not successfully authenticate. Otherwise lmtpd returns permanent failures (causing the mail to bounce immediately).

    sortcache_db: twoskip The cyrusdb backend to use for caching sort results (currently only used for xconvmultisort). Allowed values: skiplist, twoskip, zeroskip

    specialuse_extra: <none> Whitespace separated list of extra special-use attributes that can be set on a mailbox. RFC 6154 <https://datatracker.ietf.org/doc/html/rfc6154.html> currently lists what special-use attributes can be set. This allows extending that list in the future or adding your own if needed.

    specialuse_nochildren: \Scheduled \Snooze Whitespace separated list of special-use attributes that may not contain child folders. If set, mailboxes with any of these attributes may not have child folders created, and these attributes cannot be added to mailboxes that already have children.

    specialuse_protect: \Archive \Drafts \Important \Junk \Sent \Scheduled \Snooze \Trash Whitespace separated list of special-use attributes to protect the mailboxes for. If set, don't allow mailboxes with these special use attributes to be deleted or renamed to have a different parent. Default is the built-in list

    specialusealways: 1 If enabled, this option causes unextended LIST and LSUB output to include the "special-use" flags.

    sql_database: <none> Name of the database which contains the cyrusdb table(s).

    sql_engine: <none> Name of the SQL engine to use.

    Allowed values: mysql, pgsql, sqlite

    sql_hostnames: <empty string> Comma separated list of SQL servers (in host[:port] format).

    sql_passwd: <none> Password to use for authentication to the SQL server.

    sql_user: <none> Username to use for authentication to the SQL server.

    sql_usessl: 0 If enabled, a secure connection will be made to the SQL server.

    srs_alwaysrewrite: 0 If true, perform SRS rewriting for ALL forwarding, even when not required.

    srs_domain: <none> The domain to use in rewritten addresses. This must point only to machines which know the encoding secret used by this system. When present, SRS is enabled.

    srs_hashlength: 0 The hash length to generate in a rewritten address.

    srs_secrets: <none> A list of secrets with which to generate addresses.

    srs_separator: <none> The separator to appear immediately after SRS[01] in rewritten addresses.

    srvtab: <empty string> Deprecated: This option does nothing.

    submitservers: <none> A list of users and groups that are allowed to resolve "urlauth=submit+" IMAP URLs, separated by spaces. Any user listed in this will be allowed to fetch the contents of any valid "urlauth=submit+" IMAP URL: use with caution.

    subscription_db: flat The cyrusdb backend to use for the subscriptions list.

    Allowed values: flat, skiplist, twoskip, zeroskip

    suppress_capabilities: <none> Suppress the named capabilities from any capability response. Use the exact case as it appears in the response, e.g. "suppress_capabilities: ESEARCH QRESYNC WITHIN XLIST LIST-EXTENDED" if you have a murder with 2.3.x backends and don't want clients being confused by new capabilities that some backends don't support.

    statuscache: 0 Enable/disable the imap status cache.

    statuscache_db: twoskip The cyrusdb backend to use for the imap status cache.

    Allowed values: skiplist, sql, twoskip, zeroskip

    statuscache_db_path: <none> The absolute path to the statuscache db file. If not specified, will be configdirectory/statuscache.db

    sync_authname: <none> The authentication name to use when authenticating to a sync server. Prefix with a channel name to only apply for that channel.

    sync_batchsize: 8192 the number of messages to upload in a single mailbox replication. Default is 8192. If there are more than this many messages appended to the mailbox, generate a synthetic partial state and send that.

    sync_cache_db: twoskip The cyrusdb backend to use for the replication cache.

    Allowed values: skiplist, sql, twoskip, zeroskip

    sync_cache_db_path: <none> The path for the replication cache. Prefix with a channel name to apply for that channel. NOTE, it's quite important to have a different one per backend!

    sync_host: <none> Name of the host (replica running sync_server(8)) to which replication actions will be sent by sync_client(8). Prefix with a channel name to only apply for that channel.

    sync_log: 0 Enable replication action logging by lmtpd(8), imapd(8), pop3d(8), and nntpd(8). The log {configdirectory}/sync/log is used by sync_client(8) for "rolling" replication.

    sync_log_chain: 0 Enable replication action logging by sync_server as well, allowing chaining of replicas. Use this on 'B' for A => B => C replication layout.

    sync_log_channels: <none> If specified, log all events to multiple log files in directories specified by each "channel". Each channel can then be processed separately, such as by multiple sync_client(8)s in a mesh replication scheme, or by squatter(8) for rolling search index updates.

    You can use "" (the two-character string U+22 U+22) to mean the default sync channel.

    sync_log_unsuppressable_channels: squatter If specified, the named channels are exempt from the effect of setting sync_log_chain:off, i.e. they are always logged to by the sync_server process. This is only really useful to allow rolling search indexing on a replica.

    sync_password: <none> The default password to use when authenticating to a sync server. Prefix with a channel name to only apply for that channel.

    sync_port: <none> Name of the service (or port number) of the replication service on replica host. Prefix with a channel name to only apply for that channel. If not specified, and if sync_try_imap is set to "yes" (the default), then the replication client will first try "imap" (port 143) to check if imapd supports replication. Otherwise it will default to "csync" (usually port 2005).

    sync_realm: <none> The authentication realm to use when authenticating to a sync server. Prefix with a channel name to only apply for that channel.

    sync_reconnect_maxwait: 20m When sync_client cannot connect to the replica, it enters a retry loop with an exponential backoff between attempts. This option sets the upper limit on that exponential backoff: no matter how long the replica has been down so far, sync_client will never wait longer than sync_reconnect_maxwait between retries.

    If this is zero or negative, the backoff duration will be allowed to increase indefinitely (not recommended).

    If no unit is specified, seconds is assumed.

    sync_repeat_interval: 1s Minimum interval between replication runs in rolling replication mode. If a replication run takes longer than this time, we repeat immediately. Prefix with a channel name to only apply for that channel.

    For backward compatibility, if no unit is specified, seconds is assumed.

    sync_rightnow_channel: <none> if set, run sync_client to this channel immediately. As with channels, set this value to '""' to sync the default channel!

    sync_shutdown_file: <none> Simple latch used to tell sync_client(8) that it should shut down at the next opportunity. Safer than sending signals to running processes. Prefix with a channel name to only apply for that channel.

    sync_timeout: 30m How long to wait for a response before returning a timeout failure when talking to a replication peer (client or server). The minimum duration is 3 seconds, the default is 30 minutes.

    For backward compatibility, if no unit is specified, seconds is assumed.

    sync_try_imap: 1 Whether sync_client should try to perform an IMAP connection before falling back to csync. If this is set to "no", sync_client will only use csync. Prefix with a channel name to apply only for that channel.

    syslog_prefix: <none> String to be prepended to the process name in syslog entries. Can be further overridden by setting the $CYRUS_SYSLOG_PREFIX environment variable.

    Using the $CYRUS_SYSLOG_PREFIX environment variable has the additional advantage that it can be set before the imapd.conf is read, so errors while reading the config file can be syslogged with the correct prefix.

    syslog_facility: <none> Configure a syslog facility. The default is whatever is compiled in. Allowed values are: DAEMON, MAIL, NEWS, USER, and LOCAL0 through to LOCAL7

    tcp_keepalive: 0 Enable keepalive on TCP connections.

    tcp_keepalive_cnt: 0 Number of TCP keepalive probes to send before declaring the connection dead (0 == system default).

    tcp_keepalive_idle: 0 How long a connection must be idle before keepalive probes are sent (0 == system default).

    For backward compatibility, if no unit is specified, seconds is assumed.

    tcp_keepalive_intvl: 0 Time between keepalive probes (0 == system default).

    For backward compatibility, if no unit is specified, seconds is assumed.

    temp_path: /tmp The pathname to store temporary files in. It is recommended to use an in-memory filesystem such as tmpfs for this path.

    telemetry_bysessionid: 0 If true, log by sessionid instead of PID for telemetry.

    timeout: 32m The length of the IMAP server's inactivity autologout timer. The minimum value is 30 minutes. The default is 32 minutes, to allow a bit of leeway for clients that try to NOOP every 30 minutes.

    For backward compatibility, if no unit is specified, minutes is assumed.

    imapidletimeout: <none> Timeout for idling clients (RFC 2177 <https://datatracker.ietf.org/doc/html/rfc2177.html>). If not set (the default), the value of "timeout" will be used instead.

    For backward compatibility, if no unit is specified, minutes is assumed.

    tls_ca_file: <none> Deprecated in favor of tls_client_ca_file.

    tls_ca_path: <none> Deprecated in favor of tls_client_ca_dir.

    tlscache_db: twoskip Deprecated in favor of tls_sessions_db.

    tlscache_db_path: <none> Deprecated in favor of tls_sessions_db_path.

    tls_cert_file: <none> Deprecated in favor of tls_server_cert.

    tls_cipher_list: DEFAULT Deprecated in favor of tls_ciphers.

    tls_ciphers: DEFAULT The list of SSL/TLS ciphers to allow. The format of the string (and definition of "DEFAULT") is described in ciphers(1).

    See also Mozilla's server-side TLS recommendations:

    <https://wiki.mozilla.org/Security/Server_Side_TLS> .

    tls_crl_file: <none> Path to a file containing the Certificate Revocation List.

    tls_client_ca_dir: <none> Path to a directory containing the CA certificates used to verify client SSL certificates used for authentication.

    tls_client_ca_file: <none> Path to a file containing the CA certificate(s) used to verify client SSL certificates used for authentication.

    tls_client_cert: <none> File containing the certificate presented to a server for authentication during STARTTLS. A value of "disabled" will disable this server's use of certificate-based authentication.

    tls_client_certs: optional Disable ("off"), allow ("optional", default) or require ("require") the use of SSL certificates by clients to authenticate themselves. Allowed values: off, optional, require

    tls_client_key: <none> File containing the private key belonging to the tls_client_cert certificate. A value of "disabled" will disable this server's use of certificate-based authentication.

    tls_eccurve: prime256v1 The elliptic curve used for ECDHE. Default is NIST Suite B prime256. See 'openssl ecparam -list_curves' for possible values.

    tls_key_file: <none> Deprecated in favor of tls_server_key.

    tls_required: 0 If enabled, require a TLS/SSL encryption layer to be negotiated prior to ANY authentication mechanisms being advertised or allowed.

    tls_prefer_server_ciphers: 0 Prefer the ciphers on the server side instead of client side.

    tls_server_ca_dir: <none> Path to a directory with CA certificates used to verify certificates offered by the server, when cyrus acts as client. This directory must have filenames with the hashed value of the certificates (see openssl(1)).

    tls_server_ca_file: <none> Path to a file containing CA certificates used to verify certificates offered by the server, when cyrus acts as client.

    tls_server_cert: <none> File containing the certificate, including the full chain, presented to clients. Two certificates can be set, e.g RSA and EC, if the filenames are separated with comma without spaces.

    tls_server_dhparam: <none> File containing the DH parameters belonging to the certificate in tls_server_cert. Used by OpenSSL before version 3.0.

    tls_server_key: <none> File containing the private key belonging to the certificate in tls_server_cert. If not set, tls_server_cert must contain both private and public key. Two files with keys can be set, if two certificates are used, in which case the files must be separated with comma without spaces.

    tls_sessions_db: twoskip The cyrusdb backend to use for the TLS cache.

    Allowed values: skiplist, sql, twoskip, zeroskip

    tls_sessions_db_path: <none> The absolute path to the TLS sessions db file. If not specified, will be configdirectory/tls_sessions.db

    tls_session_timeout: 24h The length of time that a TLS session will be cached for later reuse. The maximum value is 24 hours, also the default. A value of 0 will disable session caching.

    For backward compatibility, if no unit is specified, minutes is assumed.

    tls_versions: tls1_0 tls1_1 tls1_2 tls1_3 A list of SSL/TLS versions to not disable. Cyrus IMAP SSL/TLS starts with all protocols, and subtracts protocols not in this list. Newer versions of SSL/TLS will need to be added here to allow them to get disabled.

    uidl_format: cyrus Choose the format for UIDLs in pop3. Possible values are "uidonly", "cyrus", "dovecot" and "courier". "uidonly" forces the old default of UID, "cyrus" is UIDVALIDITY.UID. Dovecot is 8 digits of leading hex (lower case) each UID UIDVALIDITY. Courier is UIDVALIDITY-UID. Allowed values: uidonly, cyrus, dovecot, courier

    umask: 077 The umask value used by various Cyrus IMAP programs.

    userdeny_db: flat The cyrusdb backend to use for the user access list.

    Allowed values: flat, skiplist, sql, twoskip, zeroskip

    userdeny_db_path: <none> The absolute path to the userdeny db file. If not specified, will be configdirectory/user_deny.db

    username_tolower: 1 Convert usernames to all lowercase before login/authentication. This is useful with authentication backends which ignore case during username lookups (such as LDAP).

    userprefix: Other Users If using the alternate IMAP namespace, the prefix for the other users namespace. The hierarchy delimiter will be automatically appended.

    unix_group_enable: 1 Should we look up groups when using auth_unix (disable this if you are not using groups in ACLs for your IMAP server, and you are using auth_unix with a backend (such as LDAP) that can make getgrent() calls very slow).

    unixhierarchysep: 1 Use the UNIX separator character '/' for delimiting levels of mailbox hierarchy. Turn off to use the netnews separator character '.'. Note that with the newnews separator, no dots may occur in mailbox names. The default switched in 3.0 from off to on.

    vcard_max_size: 0 Maximum allowed vCard size. If non-zero, CardDAV and JMAP will reject storage of contacts whose vCard representation is larger than vcard_max_size.

    If set to 0 (the default), a large internally-defined limit will be applied.

    If no unit is specified, bytes is assumed.

    virtdomains: off Configure virtual domain support.

off Cyrus does not know or care about domains. Only the local part of email addresses is ever considered. This is not recommended for any deployment, but is currently the default.

userid
    The user's domain is determined by splitting a fully qualified userid at the last '@' or '%' symbol. If the userid is unqualified, the defaultdomain will be used. This is the recommended configuration for all deployments. If you wish to provide calendaring services you must use this configuration.

on  Fully qualified userids are respected, as per "userid". Unqualified userids will have their domain determined by doing a reverse lookup on the IP address of the incoming network interface, or if no record is found, the defaultdomain will be used.

    Allowed values: off, userid, on

    virusscan_notification_subject: Automatically deleted mail The text used in the subject of email notifications created by cyr_virusscan(8) when deleting infected mail.

    virusscan_notification_template: <none> The absolute path to a file containing a template to use to describe infected messages that have been deleted by cyr_virusscan(8). See cyr_virusscan(8) for specification of the format of this file. If not specified, the builtin default template will be used.

    websocket_timeout: 30m Set the length of the HTTP server's inactivity autologout timer when a WebSocket channel has been established. The default is 30 minutes. The minimum value is 0, which will disable WebSockets.

    If no unit is specified, minutes is assumed.

    webdav_attachments_baseurl: <none> The base URL for WebDAV managed attachments, excluding the Cyrus-specific URL paths. Typically, this only includes the HTTP scheme and host name at which DAV clients may fetch managed attachments from, e.g. "<https://dav.example.com>". If not specified, the target host of the DAV HTTP request that uploaded the attachment will be used. For JMAP, the Link.blobId property of JSCalendar objects will be disabled.

    webdav_attachments_max_binary_attach_size: 1024K The maximum byte length of an ATTACH property value when managed attachment URIs get rewritten to BINARY during iTIP processing. Any attachment that exceeds this byte size keeps its managed attachment URI as ATTACH value. A zero size limit causes attachments of any size be rewritten as BINARY.

    xbackup_enabled: 0 Deprecated. No longer used.

    xlist-flag: <none> Set the special-use flag flag on the specified folder when it is autocreated (see the autocreate_inbox_folders option). For example, if xlist-junk: Spam is set, and the folder Spam is autocreated, the special-use flag \Junk will be set on it.

    (This option is so named for backward compatibility with old config files.)

    lmtp_catchall_mailbox: <none> Mail sent to mailboxes which do not exist, will be delivered to this user. NOTE: This must be an existing local user name with an INBOX, NOT an email address!

    zoneinfo_db: twoskip The cyrusdb backend to use for zoneinfo. This database is used by the "tzdist" httpmodules, and is managed by ctl_zoneinfo(8). Allowed values: flat, skiplist, twoskip, zeroskip

    zoneinfo_db_path: <none> The absolute path to the zoneinfo db file. If not specified, will be configdirectory/zoneinfo.db

    zoneinfo_dir: <none> The absolute path to the zoneinfo directory, containing timezone definitions as generated by the vzic tool. If not specified, whatever definitions libical finds will be used.

    If you are providing a Time Zone Data Distribution Service (i.e. you have "tzdist" listed in httpmodules), then this configuration option MUST be specified.

    object_storage_enabled: 0 Is Object storage enabled for this server. You also need to have archiving enabled and archivepartition for the mailbox. Only email files will be stored on object Storage archive partition will be used to store any other files.

    object_storage_dummy_spool: <none> Dummy object storage spool; this is for test only. Spool where user directory (container) will be created to store all emails in a flat structure.

    openio_namespace: <none> The OpenIO namespace used to store archived email messages. A namespace identifies the physical platform cyrus must contact. This directive is used by the OpenIO's SDK to locate its platform entry point.

    openio_account: <none> The OpenIO account used to account for stored emails. Accounts are unique in their namespace. They provides virtual partitions, with quotas and QoS features.

    openio_rawx_timeout: 30s The OpenIO timeout to query to the RAWX services (default 30 sec).

    openio_proxy_timeout: 5s The OpenIO timeout to query to the PROXY services (default 5 sec).

    openio_autocreate: 0 Allow the OpenIO SDK to autocreate containers. Mainly destined to be turned on development environments. In production, the container should have been provisioned with the mailboxes.

    openio_verbosity: <none> Sets the logging verbosity of the OpenIO's internal behavior. Admissible values are: "warning", "notice", "info", "debug", "trace", "quiet". The default verbosity is "warning". Set to "notice" for a few lines on a per-client basis. Set to "info" for a few lines on a per-request basis. Set to "debug" Set to "trace" to activate the underlying libcurl debug output. Enabling a verbosity higher to equal than "debug" requires the cyrus to be set in debug mode. The special "quiet" value disables all kinds of logging at the GLib level.

    caringo_hostname: <none> The Caringo hostname used to store archived email messages. A hostname identifies the physical platform cyrus must contact. This directive is used by the Caringo's SDK (CastorSDK: Caringo Simple Content Storage Protocol (SCSP) on HTTP 1.1 using a RESTful architecture.

    caringo_port: 80 The port of the caringo server (caringo_hostname); default is 80.

    fastmailsharing: 0 If enabled, use FastMail style sharing (oldschool full server paths).

SEE ALSO
imapd(8), pop3d(8), nntpd(8), lmtpd(8), httpd(8), timsieved(8), idled(8), notifyd(8), deliver(8), master(8), ciphers(1)

Author
The Cyrus Team

Copyright
1993–2026, The Cyrus Team