ospf not advertise default route

I have this setup (see pic) and it does not seem that OSPF is advertise the default route to the neighbor. I want my mpls link as the primary default gateway and my Internet link as my backup gateway with higher AD, I use default-information originate in ospf to redistribute my default gateway. But I don't see it from the core.
From the core, sh ip ro shows the last resort as 10.10.110.1. Isn't it supposed to be 10.10.100.1 (advertised via ospf from the wan router?

pic
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leblancAccountingAsked:
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JustInCaseCommented:
That is OK, meaning of that is:
You should send data to 10.10.110.1 and that router will know where to forward data from there.  
Actually, router is not advertising that route to OSPF process as default route, it advertise itself as ASBR - I have default route, I am exit from this network to rest of the world, send traffic for unknown destination to me, I know where to forward it. If you want 10.10.100.1 to be advertised as default route you need to configure default-information originate on mpls router.
MPLS router has its own routing table(s), so all traffic for your IP address range is sent to your WAN router all other traffic is sent most likely to its default route.
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leblancAccountingAuthor Commented:
My wan router knows where the Internet traffic is. It has a default route to the mpls router. I want to advertise that default route to my neighbor and the is why I did default-information originate in ospf. But the core and the fw did not receive that route. It should. Correct?
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JustInCaseCommented:
Not correct.  No need for them to have that route as long as it matches default route (and it will always match). Try to ping, traceroute or anything ... it will work ...
Your core router need to know where you Autonomous System Border Router is (ASBR), that is point where, as your OSPF process is concern, for your network  world ends. :)
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leblancAccountingAuthor Commented:
Sorry but I am so lost. I guess because my ospf knowledge is very limited. I understand the concept of ASBR, DR/BDR, etc... In my case, R1 is a ASBR because I have redistribute my default route. So I don't need to default route on my core. Correct? because via ospf, the core knows that he has to go to the ASBR to get to the Internet. So what if my mpls link fails, what happen to my backup default route "ip route 0.0.0.0. 0.0.0.0 10.10.120.1 250". Will it still work because, traffic from the core will go to R1 per the ASBR concept. Then from there, R1 has a default route to 10.10.120.1 as the exit to the Internet. Correct?

PS. What I don't understand is why core does show the last resort in the sh ip ro.

Thanks
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JustInCaseCommented:
Every routing device need to have default route, otherwise when router checks some network against it's routing table and find no matching route - traffic is dropped.
Let's say you need to ping 8.8.8.8, that network is part of any of your OSPF area - so if there is no default route on core router,  router will check its routing table and since there is no match - traffic is dropped.That's why you need default route - all traffic that does not match internal routes is sent to ASBR.

For case when link to your mpls router fails if you need to configure tracking of your default route route. Having default route with AD 250 will not help if route on primary router (R1) fails, it is still best match and router will not check by default status of static route and so it will stay in routing table of R1 router and alternative path (default route on R3) will not be used. Tracking with ip sla is way to remove static route from routing table, and since route is not in roting table will not be advertised.
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leblancAccountingAuthor Commented:
In my scenario, my mpls router and my fw router are ASBR. my mpls like is the primary link for the Internet and my internet link is the backup link. So I get rid of the floating static router with AD 250. You're correct. that does not do anything for the backup internet link.

But you said that every routing device needs a default route. In my case for the core, if I have a default route pointed to 10.10.110.1 and my mpls link goes down. How will this work, assume that the wan router knows about the backup default route from the fw router via ospf.
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JustInCaseCommented:
Default route will be advertised by R3 router also, and when default route is not being advertised from R1 (whatever is the reason) then default route from R3 will be used and default route will point to R3 as ASBR. Router R1 will also insert R3's default route until mpls router comes back online, as all other routers in the OSPF area.

You will need to use higher floating static route on R3 if you want to prevent R3 to use itself as exit point, but on primary router there is no use of it.
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leblancAccountingAuthor Commented:
"You will need to use higher floating static route on R3 if you want to prevent R3 to use itself as exit point," This is what I need to solve my issue.
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