Re: OSPF route installed when recursed via connected interface

Richard,

Static routes are preferred over OSPF by default. You can change the AD of
static routes by adding the distance to end of the route command:

ip route 192.168.0.0 255.255.255.0 <pix ip> <AD>

-hth

On Fri, Oct 2, 2009 at 7:52 AM, Richard Lowton <lowton_at_packetfreak.net>wrote:

> Guys,
>
> This is doing my head in and even if it can't be done - at least I'd like
> someone who may have done this enlighten me.
>
> Router A is connected to a /23 network on its fa0/0 interface
> Router A has a point to point link to Router B each on their fa0/1
> interface
> Router B is connected to a /23 network on its fa0/0
> Both Router A and Router B are sharing the same /23 space but at different
> geographical locations.
>
> So now we add the salt...
>
> Behind each Router and in the /23 space there is a PIX which also has a /23
> mask BUT is authoritative for one of the /24 networks within the /23 space
> and 'secondary' for the other /24 within that space. What I want to do it
> advertise both of the /24's into OSPF at each PIX into RTR_A and RTR_B. So
> I've got a couple of static routes pointing to the PIX interface for each
> /24 and then a route-map redistributing the /24's to the RTR's at each
> end...job done.
>
> The problem I see is that each of the RTR's receives the /24 networks from
> both PIX boxes BUT when the route is added to the routing table it sees the
> next hop via the /23 interface fa0/0 NOT the point-to-point link fa0/1.
>
> Diagramatically we have:
>
> PIX_A <-> fa0/0 RTR_A fa0/1 <-> fa0/1 RTR_B fa0/0 <-> PIX_B
> 192.168.0.0/23 <-> 192.168.255.0/30 <-> 192.168.0.0/23
>
> PIX_A has IP address 192.168.0.254/23
> PIX_B has IP address 192.168.1.254/23
> RTR_A has IP address 192.168.0 1/23
> RTR_B has IP address 192.168.1.1/23
>
> PIX_A is advertising networks 192.168.0.0/24 and 192.168.1.0/24 with
> metric added to the 192.168.1.0/24 network
> PIX_B is advertising networks 192.168.0.0/24 and 192.168.1.0/24 with
> metric added to the 192.168.0.0/24 network
>
> The routing table for RTR_A sees the 192.168.1.0 /24 via interface fa0/0
> The routing table for RTR_B sees the 192.168.0.0 /24 via interface fa0/0
>
> The outcome is that the routes are in the table which is great but that the
> next hop is via the wrong interface. How can we get OSPF to install the
> route so that it goes via the fa0/1 interface and not do a recursive lookup
> and send it out the connected fa0/0 interface?
>
> Cheers Gurus
> Rich
>
>
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-- 
Bryan Bartik
CCIE #23707 (R&S), CCNP
Sr. Support Engineer - IPexpert, Inc.
URL: http://www.IPexpert.com
Blogs and organic groups at http://www.ccie.net