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Redistribution question

Hi,

I am just tidying up (and removing!) some redistribution I have come across. I am just trying to work out first of all why a redistribution is not working.

Basically on one device there is EIGRP running on one set of interfaces and OSPF on another. Static and connected routes are being redistributed into EIGRP and then EIGRP is being redistributed into OSPF (see why I want to get rid!!) If I look at the EIGRP topology database I can see all the routes as expected. If however I look at the OSPF databases I can see the the routes that were originally the redistributed connected, but the route that was originally the static is not appearing in the OSPF database.

I know there are various rules for redistribution and have been trying to work out why it isn't going into the OSPF. My first thought was it was because EIGRP has to have a route in the routing table for it to be redistributed into another (and the static would prevent there being an EIGRP route) however the connected would also prevent EIGRP installing a route.

As I say this redistribution will be going but I would like to know the reason why its is not working before I do so.

Thanks

1 ACCEPTED SOLUTION

Accepted Solutions

Re: Redistribution question

Hi Mike

As for the connected interface question, I dont know but from testing it seems that it is treated differently and will be passed if it is connected.

With regards to static route redistribution, you only need the default metric set with the command or set via a route-map / within the redistribute command when it is learning routes from another protocol, not from static / connected routes as they have no metric to start with.

8 REPLIES

Re: Redistribution question

Hi Mike

The redistribute statement under OSPF doesn't have a route-map attached with an ACL denying that prefix does it.

New Member

Re: Redistribution question

No,

It does have a route map attached however both are permits and are just used to assign two different tags to routes.

Thanks

Re: Redistribution question

I have just lab'd this up and I am seeing the same as you. The only way to get that route into the OSPF database was to remove the redistribute eigrp and then redistrute static under OSPF.

What IOS are you running ?

New Member

Re: Redistribution question

Yeah,

I figured doing that would work. If the static redistribution does have to stay then my plan was to redistribute it straight to OSPF.

I bet that if there was another router running EIGRP between the the first redistribution and the OSPF that it would work. Just wanted to know for sure why it doesn't work on the same device.

I can only think that it could be the fact that EIGRP wouldn't put that route in the routing table (as the AD of a static is better) and that it treats directly connected differently as the routes EIGRP is going to be tell others about are going to be directly connected in the first place.

I don't have the IOS version to hand at the moment.

Cheers

Re: Redistribution question

That is exactly what it is, ospf is looking at the FIB ( just been schooled myslef) which has the static route hense it is not being passed across.

So what gets redistributed will be the output of show ip route

New Member

Re: Redistribution question

Brilliant thanks for that,

So you are saying it will treat the connected networks differently and redistribute them? Because obviously "show ip route eigrp" doesn't show the connected routes as they in the routing table as connected routes.

Thanks for your help! Much appreciated.

New Member

Re: Redistribution question

One further question as well if you are able to help...

From studying for BSCI I was under the impression that routes redistributed into EIGRP needed a metric setting otherwise they would not work. I know redistributing into other protocols such as OSPF a default is assigned. However I thought that with EIGRP you had to set a metric either via a default metric or by assigning it alongside the redistribute command. The static redistribution however received a set of default metrics without this configuration. Is it only dynamic protocols being redistributed into EIGRP then that need this metric setting?

Thanks

Re: Redistribution question

Hi Mike

As for the connected interface question, I dont know but from testing it seems that it is treated differently and will be passed if it is connected.

With regards to static route redistribution, you only need the default metric set with the command or set via a route-map / within the redistribute command when it is learning routes from another protocol, not from static / connected routes as they have no metric to start with.

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