Knowledgebase: E-Mail
How do I determine if my ISP is blocking SMTP access?
Posted by Nexus Support Admin on 28 March 2004 07:08 PM

To determine if your ISP is blocking SMTP port:

Open a command prompt by going to "Start" -> "Run" and typing "cmd" or "command" (depending on your version of windows).

At the command prompt, type:


If that works, then type this:

telnet 25

If you receive, "connection timed out", then your ISP IS blocking port 25 the SMTP port.

If you receive " ESMTP Exim 4.24 #1", then your OKAY.

If you received "connection timed out" then contact your ISP for more details about your block and how you can send e-mail using their mail servers.