Why don't you set the alternate ports up as the defaults when the customer signs up?
Excellent question and unfortunately I don't have an answer. I will run that one by management as it is an obviously great idea now that you mention it.
We use TLS on port 587 and SSL on 465, most mail clients default to these ports when you click the "TLS" or "SSL" box. Bonus-- we tell our clients that "we only support encrypted access to their mail". They understand.
We also support SSL access for SMTP and POP, so that could be a possibility as well. I appreciate the feedback on this from everyone. I'm still not 100% convinced that a blanket port block is the answer, but then again I'm not an ISP so my opinion shouldn't be on the top of the list of considerations either. I do have some things to think about for new customers though <g>. -Justin Scott, GravityFree