How to Configure Hot Standby Routing Protocol (HSRP) for IPv4

Hot Standby Routing Protocol (HSRP) is a Cisco proprietary protocol designed to enhance the availability of the default gateway servicing hosts on the same subnet. HSRP achieves this by providing a virtual IP address that is shared among a group of routers, with one router acting as the active router and another as the standby router. If the active router fails, the standby router immediately takes over the routing responsibilities, ensuring minimal disruption in network services.

In this blog post, we'll delve into the configuration of HSRP for IPv4, detailing the essential steps and commands needed to set up a reliable and resilient HSRP setup.

Understanding HSRP

HSRP allows multiple routers to participate in a virtual router group, sharing a virtual IP address. Within the group, routers have different roles:

• Active Router: The router currently forwarding packets for the virtual IP address.
• Standby Router: The router that monitors the active router and takes over if the active router fails.
• Other Routers: Additional routers that listen to HSRP hellos and wait to become the standby router if necessary.

HSRP Configuration Steps

To configure HSRP, follow these steps:

1. Enter Interface Configuration Mode: Specify the interface where HSRP will be configured.
2. Set HSRP Version: Ensure all routers in the HSRP group use the same version.
3. Configure Virtual IP Address: Set the virtual IP address for the HSRP group.
4. Set Router Priority: Assign a priority to each router to determine the active router.
5. Enable Preemption: Allow a higher-priority router to become active if it comes online after the group is formed.

Detailed HSRP Configuration Commands

Here’s a step-by-step guide to configuring HSRP on a Cisco router:

Step 1: Enter Interface Configuration Mode

First, select the interface you want to configure for HSRP.

    R1(config)# interface fastethernet 0/1

Step 2: Set HSRP Version

Set the HSRP version to ensure consistency across all routers in the HSRP group.

    R1(config-if)# standby version 2

Step 3: Configure Virtual IP Address

Assign a virtual IP address for the HSRP group. This IP address will be used as the default gateway for devices on the subnet.

    R1(config-if)# standby [group-number] ip [virtual-IP-address] [optional secondary]

For example:

    R1(config-if)# standby 1 ip 192.168.1.1

Ensure the other end is configured the same way:

    R2(config)# interface fastethernet 0/1     R2(config-if)# standby version 2     R2(config-if)# standby 1 ip 192.168.1.1

Step 4: Set Router Priority

Assign a priority to each router in the HSRP group. The router with the highest priority becomes the active router. The default priority is 100.

    R1(config-if)# standby [group-number] priority [priority-value]

For example:

    R1(config-if)# standby 1 priority 150

Step 5: Enable Preemption

Enable preemption so that a router with a higher priority can take over as the active router if it comes online after the initial HSRP election.

    R1(config-if)# standby [group-number] preempt

For example:

    R1(config-if)# standby 1 preempt

Verifying HSRP Configuration

After configuring HSRP, verify the setup using the following commands:

1. Show Standby: Display HSRP information for the specified interface.

    R1# show standby

2. Show Standby Brief: Provide a brief summary of HSRP information.

    R1# show standby brief

3. Debug Standby: Monitor HSRP events and troubleshoot any issues.

    R1# debug standby

Example of HSRP Configuration

Here’s an example configuration for two routers in an HSRP setup:

Router R1:

    R1(config)# interface fastethernet 0/1     R1(config-if)# standby version 2     R1(config-if)# standby 1 ip 192.168.1.1     R1(config-if)# standby 1 priority 150     R1(config-if)# standby 1 preempt

Router R2:

    R2(config)# interface fastethernet 0/1     R2(config-if)# standby version 2     R2(config-if)# standby 1 ip 192.168.1.1     R2(config-if)# standby 1 priority 100     R2(config-if)# standby 1 preempt

Configuring HSRP for IPv4 on Cisco routers ensures high availability and redundancy for network services. By following the steps outlined in this guide, you can set up HSRP to provide seamless failover and maintain network reliability. Remember to verify your configuration and adjust priorities and preemption settings to suit your network's needs. HSRP is a powerful tool in a network engineer's toolkit, providing peace of mind that critical services will remain available even in the event of a router failure.

If found helpful please share likes and comments for more 

Thank you for your valuable time 

Also Visit to know about Me: www.mdabusayed.me