Comcast Blocks My Email On Port 25 Because of Spam

So I woke this morning and tried to send an email but it wouldn’t go, I would get an Outlook 2003 error message saying:

Outlook is unable to connect to your outgoing (SMTP) e-mail server. If you continue to receive this message, contact your server administrator or Internet service provider (ISP).

The error # was 0×80042109.

I could receive email just fine.

I looked over my dedicated server and all looked good, so I sent a test from my web browser Smartermail program and it sent out just fine.

I then call my hosting company CrystalTech if they new what was going on, the tech told me to try port 8889. So I did that both in my SmarterMail admin and in the email client Outlook.

That worked! …but only for about 10 minutes and then it stopped sending email.

So then I call Comcast to ask what is going on. The tech looked at my modem and told me that they were blocking my port 25 because I might be sending out spam emails from an infected computer.

I only send out about 50 emails a day from my work computer.

I then ran a virus scan on all my computers (MS OneCare) but nothing came up.

The Comcast tech told me that my modem would release the block after 30 days and try again. In the mean time he told me to try port 587.

I had to adjust my server firewall and then I was sending email on my alternate port.

Back to normal.

Update 1/15/09: I moved my site back to the shared hosting environment and since I didn’t have control over my email server anymore I had to use 8889 which is what Crystaltech uses as their alternative port in SmarterMail.