Check network connectivity using telnet utility

Using Telnet, you can determine whether a TCP/IP connection problem is due to a misconfiguration in Handler, or is the result of a network problem. Telnet ("telnetting") provides a better means of testing connectivity than Ping. This is because of Telnet tests for connectivity over a specific port. Also, Telnet is much more thorough in its method of connectivity. Ping is like calling a phone number and hearing the ringtone at the other end; Telnet is like calling a phone number and someone picking up and answering.

Note

There are many other utilities for testing port availability. Some are easier to use (such as NotesConnect, Jping, Putty); however, since most users already have Telnet installed on a client machine, Telnet will be explored as a tool for testing connectivity in this section.

Steps to Telnet to a server over specific port (using the command line Telnet utility found in Windows):

1. Click _"Start"_ -> _"Run"_.
2. Enter telnet and click OK. You will see the Telnet command line interface.

Turn on local echo so you can see the commands you are typing by entering the following command:

Microsoft Telnet> set localecho

Connect to the server (for example, yourserver.domain.com) over a port (for example, 80) by entering the following command:

Microsoft Telnet> open yourserver.domain.com 80

If you can not connect, it means that the port is being blocked outside of the handler environment. A firewall might be blocking the port, or the server may not be running. Have the network administrator check the network configuration for hardware or software that might be blocking the port.

An unsuccessful connection attempt will look like this:

Welcome to Microsoft Telnet Client

Escape Character is 'CTRL+]'

Microsoft Telnet> open yourserver.domain.com 80
Connecting To yourserver.domain.com...

At this point, you will want to confirm the status of your connection. Enter the following command:

Microsoft Telnet> Ctrl + ]

When you pressing Ctrl+], you will be brought back to a command prompt with a flashing cursor that looks like this:

Welcome to Microsoft Telnet Client

Escape Character is 'CTRL+]'

Microsoft Telnet> open yourserver.domain.com 80
Connecting To yourserver.domain.com...
Microsoft Telnet>

Next, enter a status command and you will see the following if you are connected:

Microsoft Telnet> status

If you are connected to the server over port 80, you will see the following message:

Welcome to Microsoft Telnet Client

Escape Character is 'CTRL+]'

Microsoft Telnet> open yourserver.domain.com 80
Connecting To yourserver.domain.com...
Microsoft Telnet> status
Connected to yourserver.domain.com

Note

Windows 7 does not have Telnet enabled by default.

How to enable Telnet on Windows 7?

1. _"Start"_ -> _"Control Panel"_
2. _"Programs And Features"_
3. Check _"Turn Windows features on or off"_
4. Put a check on _"Telnet Client"_
5. Hit _"OK"_