I stand corrected from two directions, thanks Ray and Tim. The block hasn't hit here in Lafayette yet - I'll see what tomorrow brings.
As I have only a passing knowledge of iptables and firewalls in general (I'm just a lowly programmer :-)), I still don't see: 1) how a firewall can feasibly determine the originating app of a data stream on a port (key word being feasibly) 2) how the iptables rule (iptables -A FORWARD -p tcp -m tcp ! -d mail.whatever.cox.net --port 25 -j DENY) would only block traffic between servers. Looks to me like this rule would block any tcp traffic received on port 25 that was not destined for mail.whatever.cox.net, again how would COX's hardware know to allow traffic from my client to mail.somewherenotcox.net? Thanks, James Kuhns
