Thanks Nothinman , I think I am going to put another box like you said with Postfix + Cyrus on the inside network .
To TonyRic , putting so many client requests through a wan is never a good idea , I get charged for wan usage and it's extremely hard for me to judge how much traffic clients are generating . The other HUUUGE problem with this is , is that I have some POP3 clients sending usr / passes in the clear . Connecting to a local server like Nothinman said would allow me to tunnel the connections and add some sort of compression on the WAN links.
I'll report any faults / findings in this forum