Debian Firewall

Dear all,

 

I have two network, one is 192.168.1.X and other is 202.51.140.X. the 202.51.140.X is internet network. 192.168.1.X is users computers. sometimes I need to allow users to access there out side pop mail servers through the 192.168.1.X network, please help me on this matter and how I need to configure the firewall.

My Debian woody PC have two network interfaces(eth0 and eth1) and one connected to 192.168.1.X network and other connected to 202.51.140.X network.

 

Thanks..

 

suranga