View Full Version : does UPnP automatically forward ports?

2006-01-05, 04:26 PM
A friend of mine told me UPnP (included with XP) automatically forwards his ports on his router for him. I argued a lot with him about it... is it possible I'm wrong? I want to tell him he's officially on crack.

he sent me this link:

thanks in advance!

2006-01-05, 05:27 PM
It says this:

NAT Traversal Technology

NAT traversal technology allows network applications to detect that they are behind a UPnP-enabled NAT device. Then the applications can learn the shared, globally-routable IP address, and configure port mappings to forward packets from the external port of the NAT to the internal port used by the application—and all automatically so the user doesn't have to manually configure port mappings or other such rigmarole. NAT traversal allows network devices or peer-to-peer applications to traverse a NAT gateway by dynamically opening and closings ports for communication with outside services.

But IDK how it would know what port you want to forward.

2006-01-05, 05:33 PM
supposedly bitcomet tells his router somehow :wtf:

this is not possible, is it?

(oh, and I told him to stop using bitcomet)

2006-01-05, 05:54 PM
supposedly bitcomet tells his router somehow :wtf:

this is not possible, is it?

(oh, and I told him to stop using bitcomet)

It is.

If you look at most consumer routers made in the last few years from major manufacturers, upnp support is fairly standard. The NAT transversal portion of upnp is designed to solve most of the problems of users having to manually forward ports. This is particularly useful if you assign IP by DHCP on your private network. Applications can then open ports without needing to hardcode a port forward to a specific IP at the router level.

My understanding is that Azureus also supports this feature.

Note that upnp arguably has some serious security issues -- basically it is an open interface that might allow a random piece of software to modify your router settings. Almost anything behind the router can make the change. For that reason most hardware comes out of the box with upnp support turned off.

upnp does a bunch of other stuff that allow network devices to announce their presence, state capabilities, autojoin networks, etc.

2006-01-05, 06:32 PM
Azureus does support it and it works.

2006-01-06, 06:52 AM
well, I learn something new everyday! thanks for the info

so just BitComet and Azureus support UPnP? My friend is switching to utorrent now.

2006-01-06, 08:49 AM
No utorrent does too.

2006-01-06, 11:36 AM
ok, thanks