Hi, this is my first posting so bear with me. I am slighlty new to linux and have been put in charge of the servers at my new job. (So I did not do the initial setups, and still learning where all of the configurations are)

I have been having problems trying to setup clients on an internal network with access to an external mail server, but it doesn't seem to want to connect.

I have a suse box that has eth0 connected to the broaband modem, and eth1 connected to the switch, with every pc having their proxy settings pointing to the box.

I opened up the ports in Linux Firewall and Squid but I still can't connect to the external server. Is there a command to see what operation is blocking a specific port as I am getting at wits end, and every search that I made online, I see a number of people have the same problem, but the solution is never posted.
I forgot to mention that there is an internal mail server, running on postfix.

Thanks again for taking a look at the post.

**(BUMP)**

[SOLVED]

Had to masquerade the ports in the iptables.