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imapd.8cyrus - Man Page


imapd — Cyrus IMAP documentation

IMAP server process


imapd [ -C config-file ] [ -U uses ] [ -T timeout ] [ -D ]
    [ -s ] [ -N ] [ -p ssf ]


imapd is an IMAP4rev1 server.  It accepts commands on its standard input and responds on its standard output.  It MUST be invoked by master(8) with those descriptors attached to a remote client connection.

imapd reads its configuration options out of the imapd.conf(5) file unless specified otherwise by -C.

If the file msg/shutdown is created under the directory specified in the configdirectory configuration option, then imapd will shut down the connection, sending the first line contained in the file to the client as the reason.  New connections are denied.

If the file msg/motd is created under the directory specified in the configdirectory configuration option, then imapd will send the first line contained in the file to clients upon connect as an ALERT message which IMAP-compliant clients are required to display.

This option serves to annoy users mostly.  Unfortunately clients tend to connect far more frequently than is apparent, generating a separate server ALERT for each connection.  Many clients do not display these properly, if they do anything with them at all.

If the directory log/user exists under the directory specified in the configdirectory configuration option, then imapd will create protocol telemetry logs for sessions authenticating as user.

The telemetry logs will be stored in the log/user directory with a filename of the imapd process-id.


-C config-file

Use the specified configuration file config-file rather than the default 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.


Run external debugger specified in debug_command.


Serve IMAP over SSL (imaps).  All data to and from imapd is encrypted using the Secure Sockets Layer.


Bypass password checking.  (Not recommended unless you know what you're doing.)

-p ssf

Tell imapd that an external layer exists.  An SSF (security strength factor) of 1 means an integrity protection layer exists. Any higher SSF implies some form of privacy protection.


imapd is commonly included in the SERVICES section of cyrus.conf(5) like so:

    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



See Also

imapd.conf(5), master(8)


The Cyrus Team, Nic Bernstein (Onlight)

Referenced By

alpine(1), cyradm(1), cyradm(8), cyr_imtest(1), cyr_restore(8), cyrus.conf(5), fetchmail(1), httptest(1), imapd.conf(5), imclient(3), lmtptest(1), master.8cyrus(8), mupdatetest(1), pop3test(1), proxyd(8), sivtest(1), smtptest(1), sync_client(8), synctest(1).

May 06, 2024 3.8.3 Cyrus IMAP