Re: Advertising local host routes in BGP?

Interesting reading (the loop problem).
Caused by a floating static route to a multipoint if.

You say:
> The link says the solution is to point the statics to the next hop;
> which I can't, as they are local.
which triggered me to try it. And it works.

You can have a static /32 route to a next hop which is in a connected
segment. Which solves your need for a given /32 prefix to be published
by BGP w/o the burden of proxy ARP poisoning your CEF adjacency table...

-Carlos

Jeffrey Pazahanick @ 16/04/2010 0:37 -0300 dixit:
> I have a situation where I'm trying to advertise only 4 host routes
> from a /24 network to my BGP neighbors.
> As an example,
>
> #R1
> interface g0/0
> ip addr 1.1.1.2 255.255.255.0
> standby ip 1.1.1.1
>
> router bgp 1
> network 1.1.1.4 mask 255.255.255.255
> network 1.1.1.5 mask 255.255.255.255
> network 1.1.1.7 mask 255.255.255.255
> network 1.1.1.9 mask 255.255.255.255
>
> With a single router, a static route to the interface worked fine..
>
> ip route 1.1.1.4 255.255.255.255 g0/0
> ip route 1.1.1.5 255.255.255.255 g0/0
> ip route 1.1.1.7 255.255.255.255 g0/0
> ip route 1.1.1.9 255.255.255.255 g0/0
>
> When adding a redundant router, things initially work as well..
>
> #R2
> interface g0/0
> ip addr 1.1.1.3 255.255.255.0
> standby ip 1.1.1.1
>
> router bgp 1
> network 1.1.1.4 mask 255.255.255.255
> network 1.1.1.5 mask 255.255.255.255
> network 1.1.1.7 mask 255.255.255.255
> network 1.1.1.9 mask 255.255.255.255
>
> ip route 1.1.1.4 255.255.255.255 g0/0
> ip route 1.1.1.5 255.255.255.255 g0/0
> ip route 1.1.1.7 255.255.255.255 g0/0
> ip route 1.1.1.9 255.255.255.255 g0/0
>
> The issue arises when R1 fails, R2 has a CEF routing loop..
>
> Troubleshooting Cisco Express Forwarding Routing Loops
> Document ID: 26083
> http://www.cisco.com/en/US/partner/tech/tk827/tk831/technologies_tech_note09186a00800cdf2e.shtml
>
> The link says the solution is to point the statics to the next hop;
> which I can't, as they are local.
>
> Is there another way to advertise these host routes?
>
> I've been trying to use inject-maps, but my own routers are the route
> source, and it doesn't appear to work.
>
> Ideas?
>
>
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-- 
Carlos G Mendioroz  <tron_at_huapi.ba.ar>  LW7 EQI  Argentina
Blogs and organic groups at http://www.ccie.net