POP3 server process


pop3d [ -C config-file ] [ -U uses ] [ -T timeout ] [ -D ]
    [ -s ] [ -k ] [ -p ssf ]


pop3d is an POP3 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.

pop3d reads its configuration options out of the imapd.conf(5) file unless specified otherwise by -C.

If the directory log/user exists under the directory specified in the configdirectory configuration option, then pop3d 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 pop3d 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 POP3 over SSL (pop3s). All data to and from pop3d is encrypted using the Secure Sockets Layer.


Serve MIT's KPOP (Kerberized POP) protocol instead.

-p  ssf

Tell pop3d 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.


pop3d 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
    pop3        cmd="pop3d -U 30" listen="pop3" prefork=0
    pop3s       cmd="pop3d -s -U 30" listen="pop3s" 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