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Drop Interface Automatically - HSRP


I was wondering if there is anyway to automatically drop a router interface if another interface fails. I'm trying to tune HSRP, but it will not work properly if I cannot disable my WAN interface if my LAN interface fails. Any ideas?




Re: Drop Interface Automatically - HSRP


you might want to have a look at interface tracking capabilities in HSRP.

The command "standby [group-number] track type number [interface-priority]" will lower the priority of the HSRP router in case an interface goes down. You can achieve that the HSRP active router is standby in case a tracked interface goes down.

There is no possibility within IOS to shutdown an interface in case another interface goes down.

The usual behaviour is, that each WAN router tracks his WAN interface and lowers it´s HSRP priority by a value, that the former standby router becomes active. Therefore only a router with an active WAN link will be the gateway for your LAN.

A sample config could look like this:

interface Serial0

ip address ...

interface Ethernet0

ip address

interface Ethernet0/0

standby 1 preempt

standby 1 priority 110

standby 1 track interface serial0 20

standby 1 ip

Hope this helps! Please rate all posts.

Regards, Martin

Community Member

Re: Drop Interface Automatically - HSRP


Martins explanation will definitly solve your problem. one more thing is there if your WAN interface goes down HSRP interface tracking will make your standby router gateway to your LAN.and if your LAN interface goes down than also your standby router will become master router.

Community Member

Re: Drop Interface Automatically - HSRP

Thanks Martin,

I understand how HSRP works, but the problem is that my ISP will still be routing traffic to my router since the outside interface is still up. HSRP will only resolve my inside traffic going out, but is there there any way to disable the outside interface to have my ISP stop forwarding traffic? Any method outside of HSRP???



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