Scott, My ISP blocked port 25. I switched to using 2525, and that worked for a
month or so, then the ISP blocked that as well. So then I used 8025, and again, it worked for a month or so, then they blocked it.
Why would they do that? I thought the purpose of ISP's blocks on port 25 were to help isolate machines running rogue compromised bots spewing out spam and sending it directly to other recipient mail servers. They wouldn't normally be listening on anything other than port 25, so why block 2525 and 8025. Did you ISP actually detect you had email traffic on those ports and shut them off? I've never had trouble using port 2525 with either of my ISP's in getting mail to smtp.com's servers.