LMTPD(8)

NAME
lmtpd - Cyrus IMAP documentation

LMTP server process

SYNOPSIS

    lmtpd [ -C config-file ]  [ -U uses ] [ -T timeout ] [ -D ]
        [ -H ] [ -a ]

DESCRIPTION

lmtpd is an LMTP server used to deliver mail to the IMAP mailstore. It accepts commands on its standard input and responds on its standard output. It MUST be invoked by master(8) <#std-cyrusman-master-8> with those descriptors attached to a remote client connection.

lmtpd reads its configuration options out of the imapd.conf(5) <#std-cyrusman-imapd.conf-5> file unless specified otherwise by -C.

OPTIONS

-C config-file
    Use the specified configuration file config-file rather than the default imapd.conf(5) <#std-cyrusman-imapd.conf-5>.

-U uses
    The maximum number of times that the process should be used for new connections before shutting down. The default is 250.

-T timeout
    The number of seconds that the process will wait for a new connection before shutting down. Note that a value of 0 (zero) will disable the timeout. The default is 60.

-D  Run external debugger specified in debug_command.

-H  Tell lmtpd to expect a HAProxy protocol header from the sender.

-a  Preauthorize connections initiated on an internet socket, instead of requiring LMTP AUTH. This should only be used for connections coming from trusted hosts.

EXAMPLES

lmtpd is commonly included in the SERVICES section of cyrus.conf(5) <#std-cyrusman-cyrus.conf-5> like so:

    SERVICES {
        imap        cmd="imapd -U 30" listen="imap" prefork=0
        imaps       cmd="imapd -s -U 30" listen="imaps" prefork=0 maxchild=100
        lmtpunix    cmd="lmtpd" listen="/var/run/cyrus/socket/lmtp" prefork=0 maxchild=20
        sieve       cmd="timsieved" listen="sieve" prefork=0
        notify      cmd="notifyd" listen="/var/run/cyrus/socket/notify" proto="udp" prefork=1
        httpd       cmd="httpd" listen=8080 prefork=1 maxchild=20
    }

FILES

/etc/imapd.conf

SEE ALSO

imapd.conf(5) <#std-cyrusman-imapd.conf-5>, master(8) <#std-cyrusman-master-8>

Author
The Cyrus Team, Nic Bernstein (Onlight)

Copyright
1993–2026, The Cyrus Team