Please follow the steps to run telnet on Windows:
* Select the Start menu followed by the Run option.
* When presented with a text box, enter 'cmd' and hit return.
* In the MS-DOS window, enter:
TELNET 25
* Right click the MS-DOS window and "Select All". Pressing enter
will then save the results to your clipboard.
The following example means that you try to connect
remote SMTP server via PORT 25. You can try to use 26 port too.
If everything is ok you should receive something like
this:
220-_ServerName_ ESMTP Exim 4.68 #1 Wed, 06 Feb 2008 02:27:51 +0000
220-We do not authorize the use of this system to transport
unsolicited,
220 and/or bulk e-mail.
Situation when both SMTP ports (25 and 26) do not response may
indicate that mail service is not working on the server.
More information about telnet you can find here
http://www.telnet.org/