Skype for linux opens TCP and UDP port directly on router?

Discussion in 'Desktop Operation' started by blocker, Sep 13, 2012.

  1. blocker

    blocker Member


    i have noticed a strange thing. In my router there is a port forward that i did not made. It is even not visible in the manual port forwarding menu, it is only visible in the port forwarding log:

    Destination Proto. Port Range Redirect to
    all TCP 31929
    all UDP 31929

    i have tried telnet from my network, and from outside to this port, and it connects, the connection stays active 4-5 seconds then it drops

    # telnet MY_REMOTE_IP 31929
    Trying MY_REMOTE_IP...
    Connected to MY_REMOTE_IP.
    Escape character is '^]'.
    Connection closed by foreign host.

    on i have checked which service is running on this port, and guess what??? it was skype!!!

    when i quit skype, ports close, but this redirect still stays in my router table, even if i refresh.

    i have for 2 weeks reinstalled this PC with debian and downloaded skype from the official site as .deb package.

    the questions is how did skype managed to open those ports on my router and redirect them to the PC on which skype is running


    why does skype needs those ports

    i will be happy to hear your opinions!
  2. blocker

    blocker Member

    i have now disabled UPNP server, PPTP forwarding and reseted the router password, the skype again manages to open these ports

    i checked and in the skype settings the port i mentioned above is set for incoming connections

    i sniffed on that port with tcpdump, while skype was on, and it seems that there are connections to and from a number of M$ IP's...
  3. blocker

    blocker Member

    same happens when i start skype on my android phone
  4. smith23

    smith23 New Member

    mmm the same ...

Share This Page