OSPF default route injection

[bapatsubodh]

Hi,

We have IBGP and OSPF running on a router.

Learning default route via IBGP  and also getting installed in the routing table.

sh ip route

B*    0.0.0.0/0 [200/0] via *.*.*.*, -----------------------> Default route getting installed in routing table
    

Trying to inject default route in OSPF process by following command:

default-information originate always route-map Default

Route-map and prefix configuration :

route-map Default permit 10
  match ip address prefix-list Default-Route

ip prefix-list Default-Route seq 10 permit 0.0.0.0/0

Default route is not getting installed in OSPF database even though default route is available in the routing table.

If the "route-map Default" is removed from the statement the it looks like this :

"default-information originate always" and it works.

Anything related to "admin-distance" of IBGP (200)

Please share the experience any link on cisco.com?...

Thanks in adv.

Subodh

[Earl Granger IV]

You are mutually redistributing OSPF into BGP and visa versa correct?

-Earl

[bapatsubodh]

Earl,

Thanks for reply. 

There is no redistribution between IBGP and OSPF. 

OSPF process is used to generate default-route for OSPF cloud and this router is the exit point.

Similar configuration is working when BGP is "external-BGP" and not IBGP. 

Not sure if there is any basic prerequisite to have conditional-default-route installed in OSPF and that we are missing here. 

Thanks... Subodh

[Jon Marshall]

Similar configuration is working when BGP is "external-BGP" and not IBGP.

By default IBGP routes are not redistributed into an IGP. Can you add -

"bgp redistribute-internal"

under your BGP configuration and see if that makes a difference.

Jon

[Richard Burts]

Subodh

I wonder why you include the permanent parameter in your configuration of default-information originate? It seems to me that if you do not include permanent that you get the result that you want without needing the route map or the prefix list. As long as the learned default route is in the routing table then OSPF should generate the default route to its neighbors. And if the learned default route is withdrawn from the routing table then OSPF withdraws its advertised default route.

HTH

Rick

[bapatsubodh]

Thanks Rick as Jon said redis-internal command is working!

In the future we need to check some prefixes other than just the default, hence the conditional route-map is configured. Thanks for help!

subodh

[bapatsubodh]

Jon

Thanks for your replay!!

It is working once this redis. command was in. But I thought we'wd need it only when we redis between two routing protocols one of which is BGP. 

On this router default-prefix is coming from IBGP peer admin dist (200).

Similar conf is working on adjacent router where Default-route prefix is learned by EBGP peer(Peering to ISP and admin dist 20) without any redis command. 

I configured a static default route with admin dist as 199 and with "no redis" - is was working default route got installed in OSPF, then I changed admin  dist to 201 then default-route disappeared from OSPF.  

In the end it's working. :) 

Thanks for help cheers...

Subodh

[Jon Marshall]

Subodh

It is working once this redis. command was in. But I thought we'wd need it only when we redis between two routing protocols one of which is BGP. 

You need it when you redistribute BGP into an IGP and you want IBGP routes to also be redistributed because by default they aren't.

Jon