VPN redundancy with Ethernet.

Unanswered Question
Oct 8th, 2008

I have a Remote Site with 2 2811 Routers, Each Router has a SDSL connection from different Providor(i.e. Different subnet range). Terminating to a Branch Office. I'm using static routing and HSRP tracking, but my question is if the Ethernet interface for each providor does not shut down, how will the HSRP take effect. Each Ethernet interface will be connected to a each SDSL modem. There may be an issue with the Providors line but Modem connection to the 2811 Router Ethernet interface may not go down.

I have this problem too.
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BeechLiam Thu, 10/09/2008 - 02:10

Hi ,

Thanks for the reply & advise

My problem here, is that the only way for the route tracking to work , is if the Gateway (route) is unavailable. But if there is a problem on the ISP's network The ISP's Gateway (SDSL Router) may still be reachable, as it is just a connection from my routers interface to the ISP router. I'm wondering is there a way to track the IPSEC Peer instead ,thereby if the peer is unreachable the HSRP will flip.

mike_guy29 Thu, 10/09/2008 - 03:03

Hi,

I see sorry. I haven't read through this article properly so apologies if it doesn't cover what I say it does.

But I believe you can also (again IOS version dependant) track ICMP availability. E.g. can I ping www.cisco.com? If yes its up if not fail over. You can configure timers etc. Obviously this adds a slight overhead in terms of traffic.

http://www.cisco.com/en/US/docs/ios/12_3t/12_3t4/feature/guide/gtfhrp.html

The other way I believe you could go about it is configuring the two routers with IPsec High availability and detect the dead peers with DPD. I don't have any config etc to hand I am afraid but a search on IPsec High Availability may turn something up.

Thanks

BeechLiam Tue, 01/13/2009 - 08:47

I ended up using GRE tunnel with ipsec and Keepalive configuration to resolve this issue. We were aloud to pass EIGRP updates by using GRE tunneling to encapsulate the packet to pass through the Firewalls for this Dual tunnel.

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