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Beginner

Traffic seen on Standby router

                   Hello

I am currently looking at an issue whereas the standby router is still receiving traffic. There doesnt seem to be any transmitting traffic seen on the LAN or WAN interfaces. I have applied IP accounting but I cant see any traffic generating when I look at the output.

The Active/Standby router seem to be configured correctly and the metrics are lower on the primary so the LAN will use this. There is no bounces of the HSRP group, I am a bit stuck what to look at next, can anyone help?

Thanks

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6 REPLIES 6
Frequent Contributor

Traffic seen on Standby router

How are you confirming that the HSRP standby is receiving the traffic? Are you looking at the interface counters? The Standby router is still going to *some* traffic -- HSRP hellos from the active, broadcasts in the subnet, etc. What kind of platform is the standby router? If it's a switch, you can do a SPAN of the ingress port inorder to see what the traffic is.

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Posted by WebUser David Kosich from Cisco Support Community App

Beginner

Traffic seen on Standby router

Hello

Its an ASR1002 and I am checking the WAN and LAN interface counters and also have netflow configured which is showing a variety of traffic passing, RDP, HTTP, HTTPS, LotusNotes etc.

Thanks

Hall of Fame Master

Re: Traffic seen on Standby router

Sonny

Have you considered the possibility that some hosts in the subnet might be configured with a default gateway of the router physical address rather than the HSRP address?

Another possibility is that this interface has a routing protocol running which is sending routing advertisements and some device in the subnet (router or other device) is forwarding traffic based on the advertised route.

HTH

Rick

Sent from Cisco Technical Support iPhone App

Beginner

Re: Traffic seen on Standby router

Richard

Thanks for your reply, would this tie up with the fact that we are only seeing receiving traffic over this secondary?

I will check to see if the secondary is advertising routes out of the WAN that may not be advertised from the primary, to see if this is causing an issue. However from netflow I can see traffic from various sources.

I know there is BGP on the LAN side which I dont manage so its possible the issue could lie here.

Your response would be much appreciated, thanks.

Hall of Fame Master

Traffic seen on Standby router

Sonny

Perhaps if you provide some additional information about the topology it might help us to understand the issue better. Also it might be helpful if you would post some of the detail of what you are seeing in NetFlow. so that we might see what are the source addresses, what are the destination addresses, what interfaces are involved.

HTH

Rick

Beginner

Traffic seen on Standby router

Rick

Thanks for your reply, whats a good program to use so that I dont bodge something together on paint? haha.

Thanks

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