Did you also buy a Buffalo AirStation WHR-300 router and are thinking your head through how to get the port forwarding to work. I did.
I tried every possible thing and different firewall software and different computers, even updated the firmware of the router and still nothing. I decided to go for it and search for a custom firmware, because nothing else was working. It seems like that I had a faulty model or the Buffalo’s own software is faulty at this part.
I found that DD-WRT supported my router and after a few minutes of searching, I found the right firmware.
Went on to install that with the hopes of getting the shitty router to forward my HTTP port to my server and took the risk of crippling the router, but it worked like a charm! The router booted up with DD-WRT. Now after just a couple of minutes of configuration I had forwarded the HTTP port to my Linux server and just like that, I could connect to it using my public IP. Thank you DD-WRT!
If you still can’t get the server to open up, make sure you have the ports open in your local firewall and that you have forwarded the port to the right local IP address.
Hope this helps someone someday!