TCP listener test utility?

Nilzor · 03-12-2010, 03:42 AM

I need a simple tool that acts as a TCP server on a specified port for testing firewall settings. From the client side I can then simply telnet into the port and see if I get answer. Would also be nice to be able to type something from the server so that I see that the communication also works, not just the initial connection.

Does such a utility exist?

blacky_5251 · 03-12-2010, 04:03 AM

Not that I'm aware of, but you could try a couple of things to achieve the same result.

Run telnet or smtp on your test port
For example, if you run ssh on your test port, and then connect to it from the client with nc or netcat, you'll see the ssh response from the server.
Use nc or netcat to listen on the port
Running nc -l on the server test port, and nc on the client will let you test sending characters between the systems to see that traffic is getting through.

Another useful tool to monitor the server's firewall is:-

Code:

watch -d iptables -nvL

(Your distro syntax may vary)

Nilzor · 03-12-2010, 04:54 AM

Aaah thanks... Netcat is exactly what I was looking for! Guess that's a tool that should be in the toolbox of every linux user, but somehow passed me by