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HSRP Configuration on Cisco IOS



In this section we will do an HSRP configuration to understand the issue better. To do this wewill use the below topology. At the end of this article, you will find the GNS3 configuration lab of this lesson.

redundancy protocols HSRP example (Hot Standby Router Protocol) topology, protocols for redundancy

HSRP Example Topology

Before the HSRP configuration, we must prepare our topology. WE will change the router names and we will assigned the ip addresses of the router interfaces.

For the left side of the topology, we will use 10.10.10.0 network and for the right side, we will use 10.10.20.0 network. All the interfaces connected to the layer 2 swicth will be assigned with the ip addresses related to its connected port. For example the fa0/0 interface of the Site1 router will be assigned the ip address 10.10.10.1 and the GW1’s and GW2’s fa0/0 ip addresses will be 10.10.10.2 and 10.10.10.3 orderly.


After interface configuration, we will configure a static route on each Site1 and Site2. In this static route we will use two virtual ip addresses that we will explain in this article. This virtual addresses will be 10.10.10.10 and 10.10.20.20.


Site1(config)# ip route 10.10.20.0 255.255.255.0 10.10.10.10
Site2(config)# ip route 10.10.10.0 255.255.255.0 10.10.20.20

Now our configuration is ready to HSRP configuration. Let’s start on one side(left) on GW1 and GW2 and after that we will configure a second HSRP configuration for the other side(right).

GW1
GW1(config)# interface fastethernet 0/0
GW1(config-if)# standby 1 ip 10.10.10.10
GW1(config-if)# standby 1 preempt
GW1(config-if)# standby 1 priority 110
GW1(config-if)# standby 1 track fa0/1
GW1(config-if)# exit

GW1(config)# interface fastethernet 0/1
GW1(config-if)# standby 1 ip 10.10.20.20
GW1(config-if)# standby 1 preempt
GW1(config-if)# exit

GW2

GW2(config)# interface fastethernet 0/0
GW2(config-if)# standby 1 ip 10.10.10.10
GW2(config-if)# standby 1 preempt
GW2(config-if)# standby 1 priority 100
GW2(config-if)# standby 1 track fa0/1
GW2(config-if)# exit

GW2(config)# interface fastethernet 0/1
GW2(config-if)# standby 1 ip 10.10.20.20
GW2(config-if)# standby 1 preempt
GW2(config-if)# exit

You do not need to do this configuration for both sides, but in this configuration, we do it for both sites. After this you can check the configuration with “show standby” command on GW1 and GW2. As you see below, for both redundancy configuration GW1 is the active router and the GW2 is the standby.

redundancy protocols HSRP (Hot Standby Router Protocol) show standby on active router cisco

Show Standby On Active Router (HSRP)


redundancy protocols HSRP (Hot Standby Router Protocol) show standby on standby router cisco

Show Standby On Standby Router (HSRP)

To check that the traffic from Site1 to Site2 is prefering the GW1 while it is active, do traceroute from Site1. AS you see below the next hop will be the GW1.

redundancy protocols HSRP (Hot Standby Router Protocol) trace route site1 to site2

Trace Route From Router X (HSRP)

And like the same, when you start traceroute from Site2 to Site1, the traffic will choose the GW1 again, because for this redundancy session, the active router is GW1 again.

redundancy protocols HSRP (Hot Standby Router Protocol) trace route site2 to site1 cisco

Trace Route From Router Y (HSRP)

When we administratively shutdown the fastethernet 0/0 interface of GW1 for test, we see that GW2 become active by a console message and after that when we check the status, we see that it is active like below.

redundancy protocols HSRP (Hot Standby Router Protocol) show standby on new active router cisco

Show Standby On New Active Router (HSRP)

Lastly, when we start traceroute from Site1 to Site2 then we realize that the traffic is no longer go through GW1, but it is going through GW2.

Beside this basic configuration commands, we can also use the below command while configuring the redundancy with HSRP.


We use “preempt” command above but it is necessary to tell about something about this command. This command is used to force a router that has higher friority become active router. By default if a higher priority router come online, it does not become active if the preempt command is not used on it.

Another important point is “delay” command. It is use to mentione the waiting time before becoming active router.

Router(config-if)# stanby 1 preempt delay 10

You can also change hello and holder time with the below command.

Router(config-if)# stanby 1 timers 4 12

By default HSRP Hello packets are sent to the multicast address 224.0.0.2 over UDP port 1985.

There can be multiple HSRP virtual ip addresses.
Router(config-if)# stanby 1 ip 192.168.1.5
Router(config-if)# stanby 1 ip 192.168.1.6 secondary

HSRP Group is also assigned a “virtual MAC address”. For HSRP Group 8, the value is 0000.0c07.ac08.

Router(config-if)# stanby 1 mac-address 0001.0023.0456

For authentication, all the HSRP group must be configured with the same password.
Router(config-if)# stanby 1 authentication CISCO

Lastly I want to refer one point, “tracking”. During HSRP usage, there can be a problem on an interface that is critical for the connection. This interface can be other than the interface that provide standby-active routers’ connection. So, a link down in this interface can not be realize by stanby router. To overcome this issues, HSRP use “track” command that provide decreasing the priority of the router even if a specified interface become down. With this decrease, the active router is changed.

Router(config-if)# stanby 1 track fa0/1 50

I hope this artickle will be helpful for you. Let’s continue with VRRP, the standard based redundancy protocol;)

       Download HSRP Lab.

Redundancy Protocols – Part 1
Redundancy Protocols – Part 2 (HSRP)
Redundancy Protocols – Part 3 (HSRP Configuration)
Redundancy Protocols – Part 4 (VRRP)
Redundancy Protocols – Part 5 (GLBP)

You can Reach Our "CCNA Lab Courses with Packet Tracer" on Udemy.!!!
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About the Author
Gokhan Kosem is a telecommunation and network engineer. His ambition to IP networks and end-to-end system installation made him to prepare this web-site. By sharing his experiences about various networking protocols beside different system installation experiences and Cisco, Juniper, Alcatel-Lucent devices configurations, he is aimed to be helpful for his collegues in all over the world. He is currently lives in Istanbul, Turkey.

4 comments for “Redundancy Protocols – Part 3 (HSRP Configuration on Cisco IOS)”

1
Jamel

Good morning,
There is some issues with the configuration steps. In the log it shows two groups but in the configuration, only one group is configured.
I have configured both groups. When I shut down f0/0 on GW1, traffic to 10.10.10.1 becomes unreachable and traceroute from site 1 is not successful:
Site1#traceroute 10.10.20.1
Type escape sequence to abort.
Tracing the route to 10.10.20.1
VRF info: (vrf in name/id, vrf out name/id)
1 10.10.10.3 60 msec 60 msec 40 msec
2 * * *
3 * * *
4 * * *
5 * * *
6 * * *

Would you please help me fix this issue.
Thanks,

May 24th, 2014 at 10:36
2
Swaroop Shirote

Problem same

April 29th, 2015 at 16:39
3
Andrew

I find same problem. but when i shutdown both interface n GW1 it finaly switch to the other route… why was that???

December 19th, 2016 at 18:15
4
Frank

HI I need some help with a ASR 9006 has NX ios trying to connect it to a ASR 920 and not seeing the group both seem to be ACTIVE any help would be great! no standby on one of them just active on both…..
Thank you in advance
Frank

December 27th, 2016 at 20:21

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