[SOLVED] want to open my ports to play with netcat

[inlogger]

I type

Code: Select all

nc -l 75

into one terminal, and then

Code: Select all

nc localhost 75

into another terminal. and I get

Code: Select all

(UNKNOWN) [127.0.0.1] 75 (?) : Connection refused

and it happens no matter what port I choose, except 631, which I have a cups server running on.

I've tried both as my normal user and as root with no difference.

I think it doesn't work because all my ports are closed, and getting netcat to listen to one of them isn't enough to open it. If so, how can I open my ports? Otherwise, what's going on?

I also have Gtk-gnutella, and it says my computer is firewalled. My computer is behind NAT, but I have a port forwarded for my gtk-gnutella which I've TOLD it to listen to, and still it's says that it's firewalled. Could this be the same problem?

[nielchiano]

a TCP port can be in 3 states:

• non-existant, sometimes called "stealth": everything you send to it disappears
• closed: when you try to open a connection, he refuses (ie, sends a reset packet back)
• open

if you get connection refused, it's most likely just that, "closed", and probably not firewalled, since firewalls usualy do "stealth".

Maybe something: regular users aren't allowed to listen on ports < 1024; so you should try something higher.
you can also check

Code: Select all

netstat -l --inet 

to list listening ports

[inlogger]

I figured out why netcat wasn't working. I was typing "nc -l 75" when I should have been typing "nc -l -p 75" with a "-p" to specify what port to listen to (and open).

Don't know what it was making of my "nc -l 75" commands.