Using telnet to check mail connections

Using the Windows/Unix telnet command can help diagnose email related problems. To use telnet with Windows you need to open a command prompt window, to do this click the ‘Start’ button, and find ‘Command Prompt’ in the Programs|Accessories menu:

To use telnet, try the following command:

telnet 25 ie:

This checks you can access the SMTP port and you should get something back like:

If you get a response that doesn’t mention then your ISP is intercepting the connection to our server. If you don’t get any response at all, then it is likely that your firewall is blocking the connection or you have a connectivity problem.

Other commands you can try are:

telnet 225
to test access to the alternate SMTP port, or:

telnet 110
to test access to our POP3 server – for this you’ll get a different response something like:
+OK POP3 Ready