HSRP version 2 (HSRPv2) provides a redundant virtual default gateway. One router is active and another is standby; if the active router fails, the standby takes over without manual intervention. section 19.2.1 section 19.4
Key HSRPv2 facts include:
- Uses multicast address 224.0.0.102 and virtual MAC format 0000.0c9f.fXXX. section 19.2.1
- Supports 4,096 groups, numbered 0–4,095, and adds IPv6 support compared with HSRPv1. section 19.2.1 section 19.4
- Requires matching HSRPv2 version, group number, and virtual IP on participating routers; preemption is disabled by default. section 19.3 section 19.4
Two-router configuration
On R1, configure `standby version 2`, `standby 1 ip 10.0.0.1`, priority 105, and `standby 1 preempt`. Configure the same version, group, and virtual IP on R2, whose default priority remains 100. R1 becomes active; R2 becomes standby and takes over if R1 fails. section 19.3
