I have a Ubuntu box connected to a wifi router. This wifi router is connected to a d-link adsl modem/router. I am preparing this Ubuntu box to run a server that will use some special ports in UDP and TCP. I have setup this wifi router to put my Ubuntu box on a DMZ. So, the Ubuntu is on the DMZ of the wifi router, what means it is still on the local network of the D-link.
The big question is: how do I test, using Ubuntu, if these special ports are getting thru? I mean: there is some command I can type to check if a port is getting thru and certify that the computer is really on DMZ?
Part on the premise that the D-link is port-forwarding the ports correctly.