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TCP port opener for testing?

I've been looking for a tool I can use to help me test out a communications problem. I found a cool utility that does what I need but it won't run on Server 2008 R2:

http://download.cnet.com/Local-TCP-Port-Opener/3000-2085_4-10738986.html

Can anyone recommend something similar that would work for me? I need software to sit on one end of a VPN listening on specific ports so I can scan from the other side and verify that communications are up.

Rob Williams

There is a web based tool that will allow you to test if a port is open to the server from the Internet. If it might be of some help, visit the following link from the server and test for the port in question:
http://www.canyouseeme.org

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ASKER

Unfortunately that won't help me, this is a private Cisco point-to-point VPN connecting my main site to a DR center. I have to test and make sure certain ports are open before enabling a new service.

ASKER CERTIFIED SOLUTION

Qlemo

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First Last

ASKER

Hi Qlemo, that looks like it might do the job! May I ask for some guidance for the syntax? Basically I want it to listen on certain ports on the exchange server at the DR site then check from the other side if I can reach it. The documentation indicates to start it with a switch (/l) to listen but I get an error saying the hostname can't be resolved when I try that. I'd really appreciate an example line of syntax if you could spare the time. :)

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ASKER

I should have kept reading, it became clear soon enough. This is exactly what I needed, thank you Qlemo!

Qlemo

ncat --listen --keep-open --verbose 127.0.0.1 1000
listens to port 1000 on the local machine, and will give some additional info about connections when established.
echo test | ncat RemoteIp 1000 --send-only --wait 5s
should send text, and then end the connection. If the port is not reachable, it should wait for 5 seconds.