netstat: zeros at the end of the lines

I invoked the following command on a Windows XP machine:

netstat -a

The output looks ok, but at the end of some lines there are an extra "0"

...
TCP    mymachine:9006   mymachine.mydomain.com:0  LISTENING
TCP    mymachine:epmap  mymachine.mydomain.com:0  LISTENING       0
TCP    mymachine:9007   mymachine.mydomain.com:0  LISTENING       0
TCP    mymachine:32449  mymachine.mydomain.com:0  LISTENING       0
TCP    mymachine:9006   localhost:4787         ESTABLISHED
...

What is the meaning of that 0? I could find no information about it in the help

(Btw the actual problem I am trying to solve is figuring out, why I cannot connect to this machine on port 9007. All firewalls are disabled)