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.