How To Test A Mailserver

This article describes how to use the Telnet terminal program to test a connection to a mail server for POP3 and SMTP .

POP Service

Establishing a Telnet session to the MAIL server

Some ISPs (Internet Service Providers) may implement security features that may prevent Telnet access to servers within their network.

Telnet is a terminal emulation program supplied with Microsoft Windows. With Telnet, you can establish a host session to a server using one of several emulation types.

 

To establish a Telnet session, follow these steps:

1. In XP or previous Windows versions click Start > Run and type cmd and press return.
2. In Vista or Windows 7 click Start > Search and type cmd and press return.
3. In the MS-DOS window, type the following..

telnet <your mailserver> 110

3. Press the RETURN key. The Telnet window appears and displays a welcome message. This shows a successful connection to the mail server.

NOTE: The default port defined for communication to a POP service is 110. Your ISP may have defined a different port for your server. If there is difficulty establishing a connection through the default port, consult the ISP.

SMTP Service

Follow the above steps to reach the MS-DOS window and type the following..

telnet <your mailserver> 25

Press the RETURN key. You should now see a similar message as you did with port 110

Troubleshooting tip: If you do not receive a welcome message for either ports then check with your ISP to determine which ports are used on their mail servers or, double check your antivirus software to see if any port blocking is enabled.