How to configure Hot Router Standby Protocol (HSRP)
HSRP (Hot Standby Router Protocol) is a Cisco proporiaty protocol used for high availiability. The protocol can be used both on their L3 Switches and routers.
Step 1: Login to global configuration mode
# Type enable to enter global execution mode
enable
# Type Configure Terminal to enter global configuration mode
configure terminalStep 2: Create an configure an interface on R1
It can be both physcal interfaces running on native VLAN, but you can also set this settigns on a VLAN Sub interface. Set this on each interface where you need redundency
The use of Preempt command will make sure the router automatically makes a cutover to itself if seen as the router with highest priority.
int < intern interface >
ip address 192.168.1.2 255.255.255.0
standby 1 ip 192.168.1.1
standby 1 priority < 0-255 > (Highest priority wins)
standby 1 preempt Step 3: Create an configure an interface on R2
int < intern interface >
ip address 192.168.1.3 255.255.255.0
standby 1 ip 192.168.1.1
standby 1 priority < 0-255 > (Highest priority wins)
standby 1 preempt
Step 4: Additional options
Go to cisco’s own website and read about all the different HSRP options availiable, what they do and how to use them.
This feature down below allows you to track if a interface is up and use it to decrease the priority of HSRP, lets say a wan interface is down on the primary router, interface tracking will detect it an demote it to the secendary router
# In this example we are decreasing the routers priority by 100 if the interface goes down
# This setting is applied to the interface running HSRP
standby 1 track <interface> 100