Default routing in OSPF

Good Day,

I am trying to figure out how to inject a default route in ospf.

If it is single autonomous system for example area 0 do you use both the ip route command and the default-information originate command? or should the default-information originate command be used only when you are trying to share the default route informtion between autonomous systems.

Thank you.

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Comments

Forsaken_GA

In order to inject a default route, you have to have a default route. Whether that's through the ip route command to statically define one, or through a route passed down through another routing protocol makes no difference.

default-information originate is what will actually inject the default route into ospf.

Where to inject the default route is more of a design consideration.

vi_nuoc_quen_than

Assume, Your network have R1 is Border Router that connected to Internet. You can only use default-information originate in OSPF when this router have a static route to network 0.0.0.0. If you do not configure ip route, other router on your area is not receive R1 as route for network 0.0.0.0. By default, E2 is metric-type in OSPF, but you can configure E1 instead.

Inc

Also you can use the following command.

default-information originate always

Then you don't need the 0.0.0.0/0 to be in the routing table.

Xenz

Just a note, but you have 3 topics on default routes, 2 of which are asking the same thing. Maybe try to consolidate them?

skwira001

SB-K wrote: »

Good Day,

I am trying to figure out how to inject a default route in ospf.

If it is single autonomous system for example area 0 do you use both the ip route command and the default-information originate command? or should the default-information originate command be used only when you are trying to share the default route informtion between autonomous systems.

Thank you.

I'm not sure about between areas, but default-information originate is the command in config-router. You can also go into global configuration mode and use the default-network command. The guy on CBT Nuggets says the default-network command is bad. I can't remember why.

And by the way, for the CCNA, you don't need to know multiple areas anyway.

tech-airman

SB-K wrote: »

Good Day,

I am trying to figure out how to inject a default route in ospf.

If it is single autonomous system for example area 0 do you use both the ip route command and the default-information originate command? or should the default-information originate command be used only when you are trying to share the default route informtion between autonomous systems.

Thank you.

SB-K,

If you have a single autonomous system, why do you need an ip route command when you've already got the dynamic routing protocol OSPF running?