How to use Telnet to test TCP connections

Products

• Symantec Products

Issue/Introduction

You want to test a TCP connection over an IP network using standard TCP/IP suite software.

Resolution

You will need to know the IP address or fully qualified host name of the computer you are connecting to, as well as the TCP port on which the network service is waiting.

For Windows NT/2000/XP:

1. Click Start, and then click Run.
2. Type telnet and click OK.
   For example: telnet pca.mydomain.com 5631

For Windows 9x/Me:

1. Click Start, and then click Run.
2. Type telnet and click OK.
3. Click Connect, then click Remote System.
4. Enter the hostname/IP and port number in the appropriate fields.
5. Click Connect

• If you see a blank screen with a flashing cursor, which may or may not populate with data over a period of time, you are attached to a TCP port.
• If you see "Connection timed out", "Connection reset by host", "Could not open connection", or "Connection failed", either there is some sort of packet filtering between the two computers or the service is not currently waiting on the specified port.
• If you want to test a TCP service on your local computer, use the IP address 127.0.0.1. This is the reserved "local host" address.

To enable Telnet on Windows Vista and Windows 7 computers, do the following:

1. Open control panel.
2. Then go into programs.
3. Then in programs and features there should be a part that says ‘turn windows features on or off ‘ .
4. Click ‘turn windows features on or off ‘ then on the list that appears simply check the box beside: Telnet Client.
5. Then click ok.