OSPF Conditional default advertisements

[william.jackson]

Hi

I have an edge router that eBGP peers with 2 providers over a layer2 switch.

I want this router to generate a default into my network when either of the two /29's for the providers are in my routing table, I have the following but it doesnt seem to do anything?

router ospf AAA

default-information originate always route-map ospf-default

route-map ospf-default permit 10

match ip address prefix-lists Default-Check

ip prefix-list Default-Check

seq 5 permit x.x.x.x/29

seq 10 permit y.y.y.y/29

regards

[Georg Pauwen]

Hello William,

the config looks ok, I got it working in my lab in a slightly different way, you might want to try and configure it as below and see if that makes a difference:

router ospf AAA

default-information originate always route-map ospf-default

route-map ospf-default permit 10

match ip address prefix-list ISP1

!

route-map ospf-default permit 20

match ip address prefix-list ISP2

!

ip prefix-list ISP1 seq 5 permit x.x.x.x/29

ip prefix-list ISP2 seq 5 permit y.y.y.y/29

By the way, the 'always' keyword is not really significant when using the conditional route-map, since the default will only be generated when the condition is met anyway...

Regards,

GP

[william.jackson]

I have tried this but for some reason my router is still not sending out a default.

seems to very strange, as I have also done this in a lab and it works fine.

I thought the always command was for advertising a default even when a default route was not present in the routing table.

thanks for the feedback

[kamlesh_s1181]

Hi all,

Well This is about always keyword only.

Whenever you use the redistribute or the default-information router configuration command to redistribute routes into an OSPF routing domain, the Cisco IOS software automatically becomes an Autonomous System Boundary Router (ASBR). However, an ASBR does not, by default, generate a default route into the OSPF routing domain. The software still must have a default route for itself before it generates one, except when you have specified the always keyword.

When you use this command for the OSPF process, the default network must reside in the routing table, and you must satisfy the route-map map-name keyword and argument. Use the default-information originate always route-map map-name form of the command when you do not want the dependency on the default network in the routing table.

FOr that route map i am not sure but use the same route-map with always keyword i think it should work

BOL

kamlesh

[rm2017]

William - Did you ever get this working? I'm working on a similar scenario but am running the OSPF on FWSM - which does not offer the full suite of OSPF commands; therefore, causing me some issue.