Which multicast IPv4 address is used by VRRP?

The correct multicast IPv4 address used by VRRP (Virtual Router Redundancy Protocol) is 224.0.0.102. This address is specifically designated for VRRP communications between routers participating in the VRRP group.

In VRRP, multiple routers coordinate to present the appearance of a single virtual router to the hosts on the network. The master router, responsible for forwarding packets to the virtual IP address, sends periodic advertisements to the multicast address. This allows backup routers to receive updates about the status of the master router, facilitating failover and ensuring high availability of the virtual router.

The other addresses listed do not pertain to VRRP:

• 224.0.0.18 is used for the EIGRP (Enhanced Interior Gateway Routing Protocol) multicast communication.

• 224.0.0.110 is the multicast address used in OSPF (Open Shortest Path First) for routing updates.

• 224.0.0.200 is not assigned for any specific protocol widely recognized in standard network operations.

Understanding these multicast addresses is key to managing network protocols effectively and ensuring proper communication between routers within a network.