said by bairdmj:You can still filter this out no problem. I have a centrally assigned IP address setup from RADIUS and just block it in an "ospf-out" chain so all my other routers cant see it, they have no need to see it.
If you centrally assign IP addresses via RADIUS (from one common, central pool), you will inject one host route (a /32) into your IGP's (OSPF) routing table for every client who connects. Furthermore, every time one of your clients disconnects/reconnects their PPPoE connection, an update to your routing table will occur. Each device that participates in OSPF on your network will will receive the "update" every time a PPPoE connection state changes.