In a Fast Hardware Redundancy Protocol (FHRP), what should be configured as the default gateway for hosts in the subnet?

In a Fast Hardware Redundancy Protocol (FHRP) environment, the appropriate configuration for hosts in the subnet is to use the virtual IP address as their default gateway. The primary purpose of FHRP is to provide high availability and redundancy for routers within a local network.

When hosts are configured to use the virtual IP address as their default gateway, they can seamlessly communicate with the outside network even if the active router goes down. The virtual IP address acts as a stable endpoint that can be moved between the active and standby routers based on their operational states. This ensures that the hosts do not experience downtime during router failover, as the transition to the backup router is transparent to them.

Using the active or backup router's physical IP addresses as the default gateway would create a single point of failure; if the active router were to fail, the hosts would lose their gateway and network connectivity until they were manually reconfigured to use the new active router’s address. Hence, the use of the virtual IP address is crucial for maintaining constant network availability in FHRP configurations.