Port Forwarding Problems

[azrael69]

I've got an onboard LAN card and a wireless adapter.

I had previously just been using the wireless adapter, and config'd my router to forward a bunch of ports to my computer (static IP on the adapter)
Port forwarding had been working fine.

I recently plugged my Xbox into a hub, and the built-in-NIC to the hub as well, and set up ICS (XP Pro) for the Xbox to be able to get online through the router as well.

However, after I did that my port forwarding stopped entirely.
I've tried reverting settings - disable ICS, make sure the XP firewall is off, verify that i'm using a static IP, reinstall the adapter's drivers, etc. to no avail.

I've found that programs that test ports for forwarding will tell me that ports NOT being forwarded come up as "ok" but ports being forwarded come up as "NAT error"

Suggestions?!

 

[Lord Evermore]

The problem with the way you tried to set it up was that most "routers" for DSL or cable modem use are already performing Network Address Translation. ICS is essentially just a Microsoft software program that runs NAT on the computer between two interfaces. Running NAT behind NAT doesn't really work, the translations between ports and IPs just isn't meant to work that way. Plus ICS runs as a DHCP server, while your router is probably also configured as a DHCP server even if your own PC uses a static IP.

Most routers now have something like a "game mode" that is meant to allow you to connect a console directly to it in order to game online.

Make sure you've disconnected the onboard LAN port, so that it's not getting an IP address. This could be what's causing your problem, since your PC can't tell which NIC to send traffic through. You might also need to disable it in Device Manager or the PCs BIOS.

Go into your router's configuration console and verify all the port forwarding is configured. Also make sure you've rebooted the router (by actually turning the power off for several seconds, or unplugging it), in case the NAT cache hasn't cleared or the DHCP table isn't cleared.

It's not as simple to test your own ports from within your network as it is from outside. There are some websites that will do a port scan on your IP, which will then tell you if a port is open or closed. http://www.grc.com/default.htm is one easy one. Go to the ShieldsUp! page to test yourself. An Open port means that some server or application is responding on that port. Closed means the port is there, but does not have an active program using it. Stealthed means no response. If your router is configured to act as a firewall, most ports should be stealthed, while the ones you're forwarding should be either open or closed, depending on whether you have the applications running that use them.