Ok so here is my actual configuration:
Lan2 : My PC
Lan3 : A switch with other equipments
Lan5 : My Set Top Box (via a CPL adapter)
As mentioned by Draytek i'm back with the initial configuration, except for the Wan5, as requested i did it that way:
In this case here is the result:
Nothing in
Wan5To get
Wan5 "working" (geting an ip address from DHCP), i have to check
Open WAN Interface for this Channel.