A redundant gateway with HSRP

NetLab lab Intermediate 4 tasks 20 points

R1 (192.168.10.2) and R2 (192.168.10.3) both connect the LAN to CORE. The PCs already use 192.168.10.1 as their gateway, but nothing owns that address yet. Set up HSRP version 2, group 10, on both routers' Gi0/0:

Virtual IP 192.168.10.1.
R1 Active (priority 110, pre-empts); R2 Standby (default priority, pre-empts too).
R1 tracks its uplink Gi0/1 and lowers its priority by 20 when it's down.

Then test: shut down R1 Gi0/1 and check that PC1 still reaches 8.8.8.8 through R2.

How it works: this is VulnTech NetLab, a network simulator running in your browser. Click a device in the diagram to open its console and type commands, just like on real equipment (? shows help, Tab finishes a word). Click a cable to inspect it. Tasks tick themselves off as you complete them; questions are answered in the box under each task. Your work is kept if you reload; Reset starts the network over.

Solution explanation

R1 wins with priority 110. When its uplink goes down, tracking takes it to 90; R2 has 100 and pre-empts, so it becomes Active and answers for 192.168.10.1 with the same virtual MAC (0000.0c9f.f00a: f followed by the group number 10 = 00a in hex). The PCs' ARP entry for the gateway doesn't change, so they keep working.

Show solution

[R1]
enable
configure terminal
interface g0/0
standby version 2
standby 10 ip 192.168.10.1
standby 10 priority 110
standby 10 preempt
standby 10 track g0/1 20
end
[R2]
enable
configure terminal
interface g0/0
standby version 2
standby 10 ip 192.168.10.1
standby 10 preempt
end
show standby brief
[R1]
configure terminal
interface g0/1
shutdown
end
show standby brief
[PC1]
ping 8.8.8.8