I want to add second pppoe provider. I used to standart quick setup script for pppoe provider, after go to Bridge->Ports menu and disable “eth2” ( or remove ). But after dhcp server suddenly stops working ( no ip for clients, red color in menu IP → DHCP server ). Why ? And how to separate eth from bridge ?
Check how bridge gets its MAC address. By default it’s set statically to MAC address of ether2 … if you remove ether2 from bridge, you have to change bridge MAC address as well, preferably to one of bridge members ports’ MAC address. Or you can make up one, just be careful it’s not the same as any other MAC address on your LAN or nearby (including any WiFi client that might pop-up on your APs in a few years time).
Alternative is to set bridge MAC to automatic, but that has its own gotchas.