There's also an option to inject a default even if there's no default known to the router.
"Q. Can an OSPF default be originated into the system based on external information on a router that does not itself have a default?
A. OSPF generates a default only if it is configured using the command default-information originate and if there is a default network in the box from a different process. The default route in OSPF is 0.0.0.0. If you want an OSPF-enabled router to generate a default route even if it does not have a default route itself, use the command default-information originate always."
In simple words,an ospf ASBR cannot generate a default route,ie ,even if the other IGP running at ASBR(say,eigrp,rip etc) has got a default route,while redistributing these protocols ,by default ,the default routes are not injected into the ospf domain..So u require to give default-information originate command..
This command requires an explicit entry of default route in the routing table..
Now eigrp is running between R1 and R2 and ospf between R2 and R3.If R2 has got a default route learned via eigrp.When redistributing eigrp into ospf this default route is not propogated into ospf domain,ie,towards R3.In order to do so u need to configure default-information originate under ospf process.
Additionaly,this can also be used by nssa abr to inject type 7 default routes into nssa area.This does not require the default route to be explicitly present in routing table.
What the above will show is getting a default route into normal area vs. NSSA area. You can have the latter without the former. Also, think they show you don't actually have to redistribute other external routes into OSPF to redistribute an externally known default, nor even need an externally known default at all.
This is actually a pretty cool feature, i didn't even know it existed until I was looking for a solution to advertise a subnet (prefix in BGP talk), only if a certain condition existed. This is exactly what conditional advertisements does
j ai une question j ai achete un routeur cisco 887VA-k9 , je le configuré avec la configuration ci- dessous
si je le lier avec mon pc portable sur l un de ses ports directement ça marche toute est bien ( la connexion internet + m...
Attached policy provides CLI access to the Cisco 4G router over text messaging. Two files are in the attached .tar file:
2. PDF with instructions on how to load and use the .tcl file.