I'm afraid I am a complete beginner at this...
I have a Debian Linux box sitting behind a Linksys WRT54GS wireless router. It is running the SSH daemon listening on port 22. The router is serving IPs under DHCP and the Linux box has an IP of 192.168.1.103. I checked the external IP using one of those 'check my ip' sites and it is 82.xxx.xxx.xxx. Both IP's are still the same, as the Linux box and the router have never been switched off and haven't reset/crashed.
I am able to SSH into the Linux box from any of the computers on the local network (i.e. on the same side of the router).
I have set up port forwarding on the router [Port Start]=22 [Port End]=22 [Direction]=both [Destination]=192.168.1.103 [Enabled]=Yes. However, I get no response when I "Putty -ssh 82.xxx.xxx.xxx". I also get no response from "ping -ssh 82.xxx.xxx.xxx".
I would be very grateful if someone could give me some pointers on how to diagnose the source of this problem.