What is fill rule of forwarding address of OSPF LSA?
Forwarding Address is written when VRP meet the following situation.
1. OSPF is enabled on nect-hop interface of ASBR.
2. Next-hop interface of ASBR is not set as passive interface.
3. Next-hop interface of ASBR is not OSPF P2P or P2MP.
4. Next-hop interface address of ASBR is within network range of OSPF protocol.
5. Besides, FA is 0.0.0.0.
For learnt ase lsa, the next-hop points to adv rtr when forwarding address is 0. When forwarding address is not 0, the next-hop points to forwarding address.