Nmap Problem

[Loismustdie129]

I am using PCLinuxOS 2007 now. When I go into the terminal I attempt to see my open ports so i can open one for a game. When I try to run an nmap on 127.0.0.1, it returns no ports. So I guess I want to know if there is a command to show all the ports, opened or closed?

[prn]

Another way to see what is going on on various ports might be netstat.

Your open ports are already open because a particular daemon is already listening on them. You say you want to (re)open one of them for a game? Why not open a new port for the game? Most often, specific apps are coded to open specific ports. I seem to be missing something here.

There are literally thousands of ports "available" for use. In general, a program will open one for itself. I'm afraid I don't understand at all why you would want to reopen an already open port for a game. I suspect you have a major misconception of what a port is, but I cannot even be sure of that.

Basically, nmap or netstat will show which ports I actually have running programs (daemons) listening to. It would be a very bad idea, in general, to allow a game to take over, e.g., Port 22, which is basically the only way I can log into the computer from anywhere but the console.

Best Regards,
Paul

[Loismustdie129]

Well, the game isn't working right and it said that a port may be closed that needs to be opened for the online play to work. I need to check if it is open to see if the game has a bad install. I have which port it needs open written down somewhere, but I can't find it right now. So, apparently, the progam didn't open the port like it should have or the game is bad, which is what I am trying to figure out.

I tried netstat but, to be honest, I couldn't read the results.

[Motoma]

Well, the game isn't working right and it said that a port may be closed that needs to be opened for the online play to work. I need to check if it is open to see if the game has a bad install. I have which port it needs open written down somewhere, but I can't find it right now. So, apparently, the progam didn't open the port like it should have or the game is bad, which is what I am trying to figure out.

I tried netstat but, to be honest, I couldn't read the results.

The easiest way to tell if the port is open is to just try and connect to it with netcat.

# nc localhost 23847

[prn]

And if you find that you can connect with nc, then that may tell you what you have connected to, e.g.:

# nc localhost 22
SSH-1.99-OpenSSH_4.3

But in case you can't see what you have connected to, then you may want to know a little more about it and you may find out more with something like

# lsof -i tcp:22

which asks for information on what program currently owns port 22. You should get output like:

# lsof -i tcp:22
COMMAND   PID USER   FD   TYPE   DEVICE SIZE NODE NAME
sshd     2172 root    3u  IPv6     7773       TCP *:ssh (LISTEN)

which tells you that the SSH daemon (i.e., sshd) is what is listening on port 22.

HTH,
Paul