Hi altogether,

I wonder if anyone knows about a software that can show me if a certain programme, when running, opens
a port to the internet and/or keeps it open.

E.g. when using a certain desktop gadget I would be interested to know if it establishes an internet data exchange. In that case it would open a port to the internet, right?
And if there´s such a thing as a dedicated programme that shows me what programme opens a port that would really be a great help.

Any suggestions are welcome.
Thanks in advance.

Greetings
Rosika