HSRP, standby X IP SECONDARY command.

[richard_tufaro]

Hi all. I was recently doing an HSRP config. And remember a while ago, there was an issue with HSRP when doing seconday commands for a VIP that was not on the same network class as the primary IP of the interface. Does anyone know if this limitation is still there. Im using an MSFC2 12.1(20)E2 code. Posted is the config. Thanks.

interface Vlan51

ip address 172.16.1.2 255.255.0.0 secondary

ip address 10.1.51.2 255.255.255.0

no ip redirects

arp timeout 300

standby 1 ip 10.1.51.1

standby 1 ip 172.16.1.1 secondary

[Craig Norborg]

Hmmm... I think HSRP might get confused with two IP addresses using the same group. I would probably try it with different groups.

ie:

standby 1 ip 10.1.51.1

standby 2 ip 172.16.1.1 secondary

[vinodmorsa]

Hi,

The Primary, Secondary and the VIP need to be in the same subnet. I am not sure if this is related to any hardware or IOS, i tried it on msfc 2( 6500) and 3550, and 7200.

Also changing the group number will not serve the purpose( primary and secondary in diff groups does not make any sense).

Regards,

Vinod

[Craig Norborg]

Now that doesn't make sense at all. How can both a primary and secondary IP address on the same interface be in the same subnet. I don't believe IOS will even let you do that. I'm betting you didn't really look at his config and you're thinking that his primary IP is on one system and secondary is on another. Please look again, he has both a primary IP address and secondary on the same interface:

>interface Vlan51

>ip address 172.16.1.2 255.255.0.0 secondary

>ip address 10.1.51.2 255.255.255.0

>no ip redirects

>arp timeout 300

>standby 1 ip 10.1.51.1

>standby 1 ip 172.16.1.1 secondary

And in this case why wouldn't having a different HSRP group help? If he doesn't then he will have 2 IP addresses on the same physical network wanting to respond to the same MAC address. If 2 standby groups have the same group number, they have the same MAC address.