It's worth noting that C's don't need actual IP address space assigned to
the router-id for OSPF. It's just an arbitrary value; it's probably better
karma to set it to whatever you want (maybe something that doesn't look
like an IP address).
A 32-bit number assigned to each router running the OSPF
protocol. This number uniquely identifies the router within
an Autonomous System.
You can configure an arbitrary value in the IP address format for each
router. However, each router ID must be unique.
If this command is used on an OSPF router process which is already active
(has neighbors), the new router-ID is used at the next reload or at a
manual OSPF process restart. To manually restart the OSPF process, use the
clear ip ospf command.