How to find out if router is forwarding port to right computer?

[Phokus]

Ok this is my setup:

We have a computer running the freesco (http://www.freesco.org) router software for two machines. The router is using NAT; the two computers behind the router are using internal IP addresses while the router controls the external IP address. All the ports are being forwarded (except one) to a machine called 'brave'. However, the router is is setup to forward one port, 53, to a machine called 'lucky'.

Unfortunately, people cannot seem to be able to connect to my DNS server on lucky. Is there a way to see if the port is being forwarded correctly to lucky?

 

[mgpaulus]

Check out this thread: What is a good network sniffer? right here in the networking forum. Pick a sniffer for your particular OS, and then watch and see where the port 53 requests wind up. You might also check your router logs to see if they give any clues. And, is your other machine set up to actually receive the port 53 requests (is whatever service/daemon required actually started/active?)

 

[Phokus]

Sigh, it looks like that page is fore anandtech subscribers only. Do you have a link for one for linux?

 

[sohcrates]

Originally posted by: Phokus
Sigh, it looks like that page is fore anandtech subscribers only. Do you have a link for one for linux?

just substitute "subscriber" in that link with the word "forums"

voila