3

Isn't port forwarding managed by the router? Like, I've googled up some software applications that seem to port forward with great success, but it technically seems to be impossible. The packet must first go to the router. The router must forward it to the correct computer based on port forwarding rules. So how can a software application manage port forwarding if the packet must GO to the computer running this software application in the first place, meaning that port forwarding already is successful in the first place?

Rudi
  • 83
  • 4
  • 1
    +1 for a great question. I think some software utilize UPNP on routers which allows the router to open ports for an application dynamically... I'm not sure if the actual ports used can be explicitly specified though. – Dalbir Singh May 23 '10 at 18:59
  • http://stackoverflow.com/questions/333079/is-there-a-upnp-library-for-net-c-or-vb-net – kay.one May 23 '10 at 19:05

1 Answers1

4

You're seeing UPNP, which allows a program running on a local network to forward a port on the router.

SLaks
  • 868,454
  • 176
  • 1,908
  • 1,964