Using Telnet to Troubleshoot Email Connectivity Problems

Telnet is an Internet protocol that lets users log in to a remote computer with a user name and password.

Using a telnet connection can troubleshoot connectivity issues between an email server and an email client. Unsuccessful telnet connections indicate firewall or other connectivity issues. Running a telnet to one of the secure ports will fail, as that is intended due to it being secure.

Before You Start

You need to find what your incoming and outgoing (SMTP) email servers are. To find your email servers:

Log in to Web-Based Email at email.secureserver.net.
From the Help menu, select Email Client Settings.
Note your incoming and outgoing servers.

Telnet Using Windows

Windows Vista and 7 do not have Telnet installed by default. However, a user can install it by following these instructions.

Open a command prompt by clicking Start, then Run.
Type cmd and click OK.
In the command prompt window, type one of the following:
- telnet [incoming server] 110 for incoming.
- telnet [SMTP server] 25 for outgoing.
  
  If you've tried using a different SMTP port, replace 25 with that port number.
Press Enter.

Telnet Using Mac OS X

Open Spotlight by pressing Command and the space bar simultaneously.
In the Spotlight menu, type Terminal, and then press Return.
In the Terminal window, type one of the following:
- telnet [incoming server] 110 for incoming.
- telnet [SMTP server] 25 for outgoing.
  
  If you've tried using a different SMTP port, replace 25 with that port number.
Press Enter.

Reviewing Your Results

If you receive a response of "+OK" or "220" when connecting to the incoming port, then the connection was successful and the two systems can connect.

If you receive a response of "200" when connecting to the outgoing port, then the connection was successful and the two systems can connect.

If you receive a response of "Connect failed" when making either connection, it indicates network issues are preventing you from connecting to the server.