Novell SUSE Linux Openexchange Server 4.1
IMAP Clients Unable to connect on IMAP port 143.
IMAP Clients are able to connect on the secure port.
Able to telnet on port 143 but IMAP commands do not work.
Use the command to see what is holding that port open:
netstat -tupan|grep 143|grep LISTEN
You should see a output similar to:
tcp 0 0 0.0.0.0:143 0.0.0.0:* LISTEN 886/master
If you do not see master process listening, then kill the process which is listening on port 143 and restart Cyrus.