IP Connectivity Fix · Medium ~15 min · 4 devices · 4 tasks · CCNA v1.1 and v2.0

HSRP pair: wrong active router and no failover

R1 and R2 provide the default gateway 10.0.10.1 for the users on SW1 using HSRP. R1 is meant to be active, and if its uplink to R3 (Gi0/1) fails, R2 must take over. Today the two routers are not in the same HSRP group, R1 would not win the election even if they were, and R1 does not watch its uplink. Keep the virtual IP 10.0.10.1 and group 1.

R1 Gi0/0 10.0.10.2/24 and R2 Gi0/0 10.0.10.3/24 to SW1 (users) virtual IP 10.0.10.1
R1 Gi0/1 10.0.13.1/30 to R3 Gi0/0 (uplink)
R2 Gi0/1 10.0.23.1/30 to R3 Gi0/1 (uplink)

Topology

Tasks

○R1 and R2 both run HSRP group 1 with virtual IP 10.0.10.1
○R1 is the active router
○R1 preempts (takes back the role when it recovers)
○R1 tracks Gi0/1 and would drop below R2 if the uplink fails

Hints (open one at a time)

Hint 1: same group?

Run show standby brief on R1 and R2. Routers only negotiate with each other when the group number and virtual IP match.

Hint 2: who wins

The highest priority becomes active. The default is 100, and R2 uses the default. R1 needs a higher value, such as 110.

Hint 3: taking over again

Without standby 1 preempt, a router with a higher priority does not take the active role back from a router that is already active.

Hint 4: watching the uplink

standby 1 track GigabitEthernet0/1 decrement 20 lowers R1 from 110 to 90 when the uplink goes down, below R2’s 100, and R2 (which already preempts) takes over.

Full solution

R2# configure terminal
R2(config)# interface gigabitethernet0/0
R2(config-if)# no standby 2
R2(config-if)# standby 1 ip 10.0.10.1
R2(config-if)# standby 1 preempt
R2(config-if)# end

R1# configure terminal
R1(config)# interface gigabitethernet0/0
R1(config-if)# standby 1 priority 110
R1(config-if)# standby 1 preempt
R1(config-if)# standby 1 track GigabitEthernet0/1 decrement 20
R1(config-if)# end
R1# show standby brief

The decrement must push R1 below the standby router’s priority, or tracking changes nothing.

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HSRP pair: wrong active router and no failover

Stuck on a lab, or not sure what to practice next?