@lmdc45 Yeah too many failing "how to" on web, when you know how to do it with firewall rules is not that hard, but on web many do things/commands without thinking too much.
Im not very happy with this mode by using firewall, because it trigger too much the cpu when in high load of packets (like when downloading games from Steam, the cpu temperature skyrock...).
Debian has bridge-util that should do the same thing but, hopefully, better then firewall redirections.
I didnt find enough doc material on web to be sure it works and works better then my actual firewall rules so for now im stuck to this setup.
If you try that bridge-util update me with your results, i just cant ruin my setup because its necessary for my main pc-setup internet connection.