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# Cyrus Service Definitions

The Cyrus IMAP server provides service interfaces via either TCP/IP ports or Unix domain sockets. For the former, Cyrus requires that there are proper entries in the host’s `/etc/services` file. The following are required for any host using the listed services:

    pop3      110/tcp  # Post Office Protocol v3
    nntp      119/tcp  # Network News Transport Protocol
    imap      143/tcp  # Internet Mail Access Protocol rev4
    imsp      406/tcp  # Internet Message Support Protocol (deprecated)
    nntps     563/tcp  # NNTP over TLS
    imaps     993/tcp  # IMAP over TLS
    pop3s     995/tcp  # POP3 over TLS
    kpop      1109/tcp # Kerberized Post Office Protocol
    lmtp      2003/tcp # Lightweight Mail Transport Protocol service
    smmap     2004/tcp # Cyrus smmapd (quota check) service
    csync     2005/tcp # Cyrus replication service
    mupdate   3905/tcp # Cyrus mupdate service
    sieve     4190/tcp # timsieved Sieve Mail Filtering Language service

Make sure that these lines are present or add them if they are missing.

## Controlling Service Ports and Sockets

The actual port or socket used by any given service may be controlled in the service definition line for that service in the cyrus.conf(5) file, using the `listen=` directive. Please consult the cyrus.conf(5) man page for details.