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 and add them if they are
missing.
