do email clients use just ports 25 and 110??? or do they use others as well???

because when i have my server firewall running, and enable access to port 25 and 110 email clients are still not able to connect, getting a connection refused error.

when i stop the firewall, clients connect fine

so are there any other ports i need open, or does anyone know a reason why this is happening

thanx

Make sure that you're allowing any source port to connect to those destination ports, and that you're letting the server's response back out.

Also, if you're clients are using IMAP, it uses different ports.

Greetings:

From http://www.wemanageservers.com/monitoring/port_monitoring/common_ports/common_ports.html

SMTP is port 25
POP3 is 110

You may want to check if they are using IMAP. Also, while there are standard ports, ports can be re-mapped. So you should really check to see what's running on what port.

lsof -i | egrep 'COMMAND|LISTEN|Idle'

is a good command to run on the box to see what ports are open.

Then you can run nmap or nessus or another security / port scanner from a separate box to confirm et all.

Thank you.