Determining all ports used on a network

[Luvsql]

I have to create a website and assign it to a port number, but want to be sure it is currently not used by any port on our network, by any of our servers. IS there anyway of scanning active ports on a network?

 

[kmcferrin]

I'm not sure why it matters if that port is being used elsewhere on your network. The only thing that should matter is whether that port is already in use on your web server. You can have two web servers on the same network using port 80, because the servers will have different IP addresses. So one site could be hosted at 192.168.10.2:80 and the other at 192.168.10.3:80 and there would be no conflict (I just pulled those IP addresses out of the private address space, so they wouldn't work on the Internet).

If you want to see what ports are already in use on your server, you can do a "netstat -a" and it will show you ports that are in active use. If you're worried that you might grab a port that is used by some other service, you should just make sure that you're not using one of the "Well-known ports" and you should be fine. Most people use port 8080 to run a second web site on the same server. Microsoft explains how ports are broken out and provides a link to the list of registered ports in this article:

http://support.microsoft.com/kb/174904/en-us

 

[kmkeshav]

I agree with kmcferrin.