How do you know what port is free

[Retrospect]

Talking about a PC
I have always wonder what ports are not used, and what ports are used.
How do you find out

Isn't ports are listed from 1 to 65535? You can choose any of these number in this range..?

 

[mdeezy]

can you be more specific...

 

[riser]

1-1023 are standard ports meaning they have protocols assigned to them.

Go to a command prompt (start, run, type CMD and click OK) and type:

Netstat
or
Netstat -A

 

[Retrospect]

the command does help but I don't understand all of the lines. You know in Windows Vista Ultimate, if you go to task manager under services or resources monitor it gives your a lot of information about the system services. The only thing it doesn't show is port being used per what program. Are there any third party program that allows you to monitor all of these task?

Thanks

 

[exo232]

you can scan yourself using this tool
http://www.t1shopper.com/tools/port-scanner/

although it only works if your currently accepting connections on that port

 

[gomerpile]

myself I use nettools port scanner it is the best to do portscanning

The ports that are in the open port list you will not use for they are being used by app or autoupdates or sql server