You can run a simple test to see if your ISP is blocking port 25. Open a command prompt for windows or Terminal.app for OS X and type in the commands below.


telnet domain.com 25


If your ISP is blocking port 25 you will not get a response back. However if it isn't blocking port 25 you will see an output similar to the one below.


[user@host:~]$ telnet domain.com 25
Trying xxx.xxx.xxx.xxx...
Connected to domain.com.
Escape character is '^]'.
220-host.domain.com ESMTP Exim 4.52 #1 Wed, 16 Aug 2006 20:15:23 -0400
220-We do not authorize the use of this system to transport unsolicited,
220 and/or bulk e-mail.


Note: This response above is one of many that you can receive. The one you may receive may not look the same, however getting a response means that port 25 is unblocked.

Add to Favourites
Print this Article