Blocked Port 25 Workaround

Recently, I switched to AT&T DSL. I’m quite happy with the price of $19.95/month. Of course, there was a drawback; they block port 25, the port used to send email. I figured that out after an hour of searching. There are a few solutions for this. Here are my findings.

Update: I use sendmail on a linux  server to run my email.

Solution 1: Change the listening port
This is the most obvious fix, and the one I implemented. You need to admin your own server to do this. Using sendmail, it’s only 2 lines in sendmail.mc:


define(`RELAY_MAILER_ARGS', `TCP $h 2525')dnl
define(`ESMTP_MAILER_ARGS', `TCP $h 25')dnl

The first line changes the smtp port to 2525, and the second line changes the outgoing smtp port back to 25. Without the second line, no email will go out.

Note: when editing the sendmail.mc, you need to compile it by running make or m4 sendmail.mc > sendmail.cf. After compiling it, restart the sendmail daemon. DO NOT EDIT sendmail.cf!

Solution 2: Use a proxy
There are plenty of services out there that will proxy, or relay, for a fee. I am sure there are proxies that are free, but I wouldn’t trust them to keep my information private for a second.

This solution doesn’t require you to have admin rights on the server and it is a lot easier. Each proxy setup is different, so follow the instructions they give.

Solution 3: Don’t send email with that account
Not the best solution, but you can get a yahoo or gmail account for free. You can still receive email from any account. This is probably not acceptible for most people.

Solution 4: Switch to another ISP
This is always an option, even if it means downgrading to dial-up. The only reason why I am keeping AT&T is because of the price.

Well, I hope that you found this information helpful. Happy e-Mailing.