Question

How can you find out which process is listening upon which port on Windows and Linux?
Are there some Applications explicitly monitoring?

Answer 1

On windows 7, you can use

netstat -b -a

netstat /?

-b      Displays the executable involved in creating each connection or
          listening port. In some cases well-known executables host
          multiple independent components, and in these cases the
          sequence of components involved in creating the connection
          or listening port is displayed. In this case the executable
          name is in [] at the bottom, on top is the component it called,
          and so forth until TCP/IP was reached. Note that this option
          can be time-consuming and will fail unless you have sufficient
          permissions.
-o      Displays the owning process ID associated with each connection.

On Linux use, -p needs root privileges.

#netstat -p

#netstat -h
-p, --programs           display PID/Program name for sockets