Countless hours of research have lead me to believe that nothing would work. Oh sure one Xbox open at a time is sometimes fine, But when you want to play with up to 5 360’s from the same hose/connection, you need a little somethign special. DD-WRT FTW! I have a Linksys 160N and tried countless ways only had one at a time and for a brief period 2. But then after spending $200 on a “”SUPER”” router and still ZER0 luck i decided. to return that router. Well i wanted to try DD-WRT for a little while but cretin thingsgs i wanted were not supported yet. And then i checked back 2 months ago and BAM! There it was. everything was supported.
It just happens that after i did all my configuration , ALL 5 XBOX 360’s then had OPEN NAT TYPE! After many Trials Using the DD-WRT (or other custom Firmware) is the only way to have all ports open. Just remember to follow they instructions to the LETTER!!!! Oh don’t forget to Enable the Upnp server!
The quick and Dirty:
WRT160N
DD-WRT V24 SP1
5 XBOX 360’s
CHECK!! OPEN NAT TYPE!