Testing TCP Ports with Telnet

jskfan
jskfan used Ask the Experts™
on
I know when it comes to  testing TCP ports that are open, Administrators use Telnet.
However most of the time Telnet service is not enabled on local PCs as well as on remote Servers.
It is a tedious process each time you need to test a port , you will have to enable Telnet service on local and Remote computers.

Any alternate tools ?

Thanks
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use nmap instead. search for nmap for windows  or download from here http://nmap.org/download.html
Qlemo"Batchelor", Developer and EE Topic Advisor
Top Expert 2015
Commented:
That is plain wrong. You use telnet against a specific port, not against a telnet server. Of course you need to have the telnet *client* installed on the local machine, otherwise you cannot use the command (indeed you only need the telnet.exe).

Having said that, other tools are better suited for testing ports. There are lot of them - nmap, netcat, and many more. It depends on whether you need to test a single port only, or perform a port scan to get an overview.

Author

Commented:
I know if you have Telnet service enabled on the client and on the server you can test the TCP port, but most of the time for security reason Telnet service is disabled on windows computers
I wonder if SSH can be installed and enabled on the client and can be used without having to install it on the server ? which I doubt it

I am looking for a tool that tests  from the client to the server whether a certain port is open, if the tool scans all the ports open on a certain server that's fine too
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"Batchelor", Developer and EE Topic Advisor
Top Expert 2015
Commented:
Did you read what we posted? You just repeated what you told in the question, and we answered most of it.
"if you have Telnet service enabled on the client" - again, no telnet service on client needed.
Also, if you want to test any other port than the telnet port (23/tcp), you do not need the telnet server on the target machine.
The idea and suggestion to use the local telnet client for testing ports has its origins in the fact that telnet client has been installed by default on Windows OS in the past. With more recent OS (starting with Vista) telnet.exe is an optional component, but still part of the OS installation, and hence considered more "secure" than 3rd-party tools.

In regard to SSH: you need  a SSH server, which is nothing else than telnet using SSL/TLS encryption. No, doesn't work for testing ports.

Again: nmap, netcat, SuperScan, Angry IP Scanner and many many more tools are available for free. nmap and Angry IP Scanner are very popular. If you want to have more suggestions, search for "port scan tool".

Author

Commented:
I will test nmap and  let you know
Thank you

Author

Commented:
Thank you

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