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Re: BGP Design question.


From: Ingo Flaschberger <if () xip at>
Date: Thu, 23 Jun 2011 01:07:54 +0200 (CEST)

Hi Bret,

To keep this scenario simple, I'm multihoming to one carrier.
I have two Netiron CERs. Each have a eBGP connection to the same peer.
The CERs have an iBGP connection to each other.
That works all fine and dandy. Feel free to comment, however if you think there is a better way to do this.

Here comes the tricky part. I have two firewalls in an Active/Passive setup. When one fails the other is configured 
exactly the same
and picks up where the other left off. (Yes, all the sessions etc. are actively mirrored between the devices)

I am using OSPFv2 between the CERs and the Firewalls. Failover works just fine, however when I fail an OSPF link that has the active default route, ingress traffic still routes fine and dandy, but egress traffic doesn't. Both Netiron's OSPF are setup to advertise they are the default route.

Linux firewall?
disabled rp-filter?

What I'm wondering is, if OSPF is the right solution for this. How do others solve this problem?

I do something similar with freebsd; you always make shure the backbone area 0.0.0.0 does not break into 2 parts, perhaps use an extra link between the 2 firewalls just because of this.

Kind regards,
        Ingo Flaschberger


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