HSRP not working

Unanswered Question
Oct 6th, 2008

Hi,

I have configured two sub interface inorder to setup 2 DHCP in a router and HSRP between two routers,

HSRP is working for .10 and but not the .71, Config is pasted below for further reference.

Out puts of both router's and config is attahched please refer the same

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Overall Rating: 4 (1 ratings)
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mycla9_123 Mon, 10/06/2008 - 00:52

Can you please upload the network diagram? How did you interconnect the 2 routers? Is there any switch in between?

It seems that you have 2 VLANs, vlan 10 and 71.

satish_zanjurne Mon, 10/06/2008 - 00:59

Hi

In "show standby" output the group is duplicate.

Have you added one more group with same group id 1 under interface fastethernet 0/1 ??

Maybe that is causing problem.

HSRP Group ID should be unique.

HTH...rate if helpful..

mycla9_123 Mon, 10/06/2008 - 00:59

I assume that you have a switch between 2 routers

You should do this:

Proposed config on B1 router

New config for LAN - Data and WIFI

===================================

interface FastEthernet0/0

no shutdown

!

interface FastEthernet0/0.10

description #### DATA ####

encapsulation dot1Q 10

ip address 172.24.3.7 255.255.255.0

standby 0 ip 172.24.3.1

standby 0 preempt

standby 0 priority 150

!

interface FastEthernet0/0.71

description #### WIFI ####

encapsulation dot1Q 71

ip address 172.24.71.7 255.255.255.0

standby 1 ip 172.24.71.1

standby 1 preempt

standby 1 priority 150

Proposed config on B2 router

New config for LAN - Data and WIFI

===================================

interface G0/0

no shutdown

!

interface GigabitEthernet0/0.10

description #### DATA ####

encapsulation dot1Q 10

ip address 172.24.3.5 255.255.255.0

standby 0 ip 172.24.3.1

standby 0 preempt

standby 0 priority 140

!

interface FastEthernet0/0.71

description #### WIFI ####

encapsulation dot1Q 71

ip address 172.24.71.5 255.255.255.0

standby 1 ip 172.24.71.1

standby 1 preempt

standby 1 priority 140

Please rate it if it helps

dipumj Mon, 10/06/2008 - 01:16

Hi,

thanks for your reply but wondering . why no shutdown is require in the Fa0/0 and G0/0 as this are in use now.

Giuseppe Larosa Mon, 10/06/2008 - 01:57

Hello UCB,

before your router FE interfaces had ip addresses on the physical interfaces : now you want to use 802.1Q subinterfaces.

In order to that the switch ports must be configured as trunk ports with 802.1Q encapsulation and allowing vlan 10,71.

Remember also to declare the vlan 10 as native

Example of cfg on switch side:

int g0/15

switchport

switchport trunk enc dot1q

switchport trunk native vlan 10

switchport trunk allowed vlan 10,71

to find out what is the switch port

do

sh cdp n f0/0

There is no communication in vlan 71 between the two routers this means they are not sharing a broadcast domain

Hope to help

Giuseppe

donlerche Mon, 10/06/2008 - 11:57

Hi,

The reason for your issue is shown in the output for router B1, you have a duplicate for HSRP group 1. Now that you have moved the subnet 172.24.3.0/24 from fa0/0 to subinterface fa0/0.10 you should remove the ip address and standby ip from fa0/0, i.e.

interface FastEthernet0/0

no ip address 172.24.3.7 255.255.255.0

no standby ip 172.24.3.1

Although no specific standby group was associated with fa0/0 it has used group 1 as default, and this has conflicted with your new group 1 defined for subinterface fa0/0.71

Hope this helps

Don

Giuseppe Larosa Mon, 10/06/2008 - 13:04

Hello Don,

from sh standby you can see the third HSRP group is number 1 but out f0/1 not f0/0.

I had the same doubt but it is not possible to have overlapping ip addresses on LAN interfaces you get an error on the router if you try to do this.

However, it is possible that physical interface config still needs to be cleaned from the standby command but without ip address on main interface.

Hope to help

Giuseppe

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