The first thing you’ll want to do is probably to add “net.ifnames=0” to your kernel command line to disable network interface renaming.
The next thing you’ll need to do is make sure you bring up eth0 (no address is needed, it just needs to be up) before bringing up wan. You can do this by adding “pre-up ifconfig eth0 up” to your /etc/network/interfaces stanza for wan.
