we use policy based routing with two default routes (two different routing marks).
We need default routes for unmarked traffic as well. Therefore we have two default routes without routing marks.
One is the primary (distance 1) and one the backup (distance 2). This works great so far.
Unfortunately the primary uplink has a DHCP-IP. Now we have update the route for unmarked traffic each time the WAN-IP changes.
We would need a script that checks if the gateway of the dynamic route (WAN-KDE) has changed and update the gateway of the static route (for unmarked traffic).