linux| firewall| windows: open a socket , test a port

Question

I have a Linux machine.

The network has a very restrictive firewall config.

I want to reach this machine from a Windows computer using port 4449.

How can I test if communication is working correctly?

• Open a socket and listen on port 4449. In Linux how? Using which utility?
• Test the connection from Windows: telnet, or something else?

Answer 1

netcat is an utility that is included in many Linux distributions.

To listen on TCP port 4449 try

nc -v -l 4449

And on the client telnet should be perfect

Answer 2

what do you mean when you say "the network has very restristive firewall config"? What firewall you're using? By iptables is done so:

iptables -A INPUT -o eth0 -p tcp -m tcp --dport 4449 -j ACCEPT

To test:

telnet o xxx.xxx.xxx.xxx 4449