SLES 10 SP3 based Server (Nows SBE 2.5)
can't access IMAP from Workstation
Single Network card connected to external NAT Adsl router

Firewall not configured (checked set to manual)

Email works - Port 25 opened in Router
VNC works on port 5900

Need to use IMAP
so opened Port 143 on the router but can't access

Also opened 5901 but VNC does not work on 5901

Tried "Telnet Server IP 143" - from Workstation does not work
but "Telnet Server IP 143" from Server console does not work...

What do I need to do or check ?
are there some filter setup?...

(my Linux kowledge is very limited)