Filtering OSPF to EIGRP redistribute with route-map

[tjalbrecht]

Hello,

I have an OSPF and EIGRP network that I am working on converging.  However, my route-map filters do not seem to be working correctly.  The general setup is as such:

OSPF:

192.168.0.0/24

192.168.1.0/24

EIGRP:

10.10.5.0/24

10.10.6.0/24

Network that joins the two:

172.16.0.0/30

I have the following configured on the EIGRP side.  When I turn up OSPF between the two networks, I receive the routes, but I am also receiving ALL of the OSPF routes, not just 192.168.0.0/24 and 192.168.1.0/24:

router eigrp 100

redistribute ospf 100 route-map A2B

no auto-summary

network 172.16.0.0 0.0.0.3

network 10.10.5.0 0.0.0.255

network 10.10.6.0 0.0.0.255

router ospf 100

log-adjacency-changes

redistribute eigrp 100 subnets route-map B2A

network 172.16.0.0 0.0.0.3 area 1

ip prefix-list B2A description OSPF-EIGRP_Redistribution

ip prefix-list B2A seq 5 permit 10.10.5.0/24

ip prefix-list B2A seq 10 permit 10.10.6.0/24

ip prefix-list A2B description EIGRP-OSPF_Redistribution 

ip prefix-list A2B seq 5 permit 192.168.0.0/24

ip prefix-list A2B seq 10 permit 192.168.1.0/24

route-map B2A permit 10

match ip address prefix-list B2A

route-map A2B permit 10

match ip address prefix-list A2B

Am I missing something for the filter to work properly?

Thanks,

T.J.

[Richard Burts]

TJ

With the configuration that you have posted I am surprised that you are getting any OSPF routes redistributed into EIGRP. Your configuration of EIGRP does not provide any default metric, and without default metric EIGRP will usually not redistribute routes from another protocol.

Are you sure that OSPF routes are redistributed into EIGRP? When you do show ip eigrp topology are you seeing OSPF routes in the topology table of EIGRP? If so it might be helpful if you would post the output of show ip route and the output of show ip eigrp topology.

HTH

Rick

[tjalbrecht]

I have edited my actual addresses to ficticious RFC1918 for my posting, without using my actual networks, so I won't be able to display the outputs you requested here.  When I do a show ip route from various points within the EIGRP network, I am seeing OSPF routes from both within the filtered subnets that I desire, and outside of the filtered subnets that I would like blocked.

My goal, is to apply a filter to only see a few OSPF subnets from within those various points in the EIGRP network.  Right now, I am seeing all of the subnets.

[Richard Burts]

TJ

Even if you can not post the results I would still ask you to look into the output of show ip eigrp topology and see if the OSPF routes are in the topology table of EIGRP? And if they are in the topology table, then where is EIGRP learning those routes? Is it possible that there is some other router which is also doing redistribution?

HTH

Rick

[tjalbrecht]

Ahh, I see.  Yes, the information I have posted is for the EIGRP gateway router, (let's call this router B) which is part of the former EIGRP core.  The adjacent network, running OSPF, has a different gateway router (let's call this router A) directly connected to this router via a /30.  172.16.0.0/30 is the gateway subnet that I have in the example, used for distributing OSPF routes into the EIGRP network, and the EIGRP routes into the OSPF network.

I will turn the OSPF gateway up again tonight and observe the topology table.  Last time I turned it up, my EIGRP network was displaying all of the OSPF routes in the "show ip route", not just the ones listed in the filter.

Thank you,

T.J.

[Richard Burts · Accepted solution]

TJ

It is the expected behavior that the router running both OSPF and EIGRP and redistributing OSPF into EIGRP will show all of the OSPF routes in the output of show ip route. After all that router is running OSPF and learning the OSPF routes. So those routes should be in the routing table.

But being in the routing table does not indicate that they have been redistributed. That is why I am emphasizing to look into the EIGRP topology table. The topology table will show what routes have actually made it into EIGRP and will be advertised to EIGRP neighbors.

HTH

Rick

[tjalbrecht]

Richard, thanks for your help.  Your information pointed me in the right direction.  You were correct, only that gateway router was seeing the OSPF routes, and it was not redistributing them throughout my EIGRP topology.  After specifying the 'set metric' in the route map, I was able to see the OSPF routes in my EIGRP table.

The next step was filtering them on the gateway router.  Instead of using a prefix-list, I used an ip access-list to list the appropriate subnets, and filtered them using the 'distribute-list xx in FastEthernet1/0/x' command.

Thanks!

T.J.

[Richard Burts]

TJ

I am glad that you got it worked out and that my suggestions were helpful in identifying the issue and finding a solution. Thank you for marking the issue as resolved (and thanks for the points). It makes the forum more useful when people can read about an issue and can know that they will read a resolution to the issue. Your marking makes this evident to readers of the thread.

HTH

Rick

[tjalbrecht]

One last add-on:  How would I add the default route to this list?

I read this page:

http://www.cisco.com/en/US/docs/ios/12_0s/feature/guide/routmap.html#wp1047691

And that page shows the 0.0.0.0 without a mask on the access list.  My list currently has subnet masks for the rest of the allowed routes:

access-list 65 remark EIGRP-OSPF_Redistribution

access-list 65 permit 192.168.0.0 0.0.0.255

access-list 65 permit 192.168.1.0 0.0.0.255

Would I simply add:

access-list 65 permit 0.0.0.0

To my list?  It just seems that might not be complete, or might let in too many routes?

Thanks,

T.J.

[Richard Burts]

T.J.

In a standard access list there is an implicit mask for an entry. If you enter access-list 65 permit 0.0.0.0 that is fine and what the IOS will process is actually access-list 65 permit 0.0.0.0 0.0.0.0.

This is the correct entry to permit the default route. It will not permit any route other than the default route.

HTH

Rick

[Zulqadar Ahmad]

Hi Thomas ,

I am facing same problem have you find any solution for this please have a look my configuration ........

router ospf 1

log-adjacency-changes

redistribute eigrp 1

network 173.15.254.1 0.0.0.0 area 1

router eigrp 1

redistribute ospf 1 route-map option-1

network 175.15.254.1 0.0.0.0

default-metric 1500 10 255 1 1500

no auto-summary

route-map option-1, deny, sequence 10

  Match clauses:

    ip address (access-lists): match-101

  Set clauses:

  Policy routing matches: 0 packets, 0 bytes

route-map option-1, permit, sequence 100

  Match clauses:

  Set clauses:

  Policy routing matches: 0 packets, 0 bytes

Extended IP access list match-101

    permit ip host 172.16.2.0 host 255.255.255.252

    permit ip host 172.16.3.0 host 255.255.255.252

I just want to filter only these two routes 172.16.2.0/32 and 172.16.3.0/32 but i m recieving all OSPF routes in EIGRP topolgy table

sh ip eigrp topology | i 172.16.

P 172.16.4.0/32, 1 successors, FD is 1716736

P 172.16.5.0/32, 1 successors, FD is 1716736

P 172.16.2.0/32, 1 successors, FD is 1716736

P 172.16.3.0/32, 1 successors, FD is 1716736

And these route could be seen every EIGRP neighbour .....

Thanks,

Zulqadar

Message was edited by: Zulqadar Ahmad

[cadet alain]

Hi,

can you try this:

ip prefix-list FILTER deny 172.16.2.0/30

ip prefix-list FILTER deny 172.16.3.0/30

ip prefix-list FILTER permit  0.0.0.0/0 le 32

route-map FILTER permit 10

  match ip address prefix-list FILTER

router eigrp 1

redistribute ospf 1 route-map FILTER

Regards.

Alain

Don't forget to rate helpful posts.

[Zulqadar Ahmad]

Hi Alain,

Thanks for ur help but i have tried as you mention but the problem is same......

router eigrp 1

redistribute ospf 1 route-map FILTER

network 175.15.254.1 0.0.0.0

default-metric 1000 33 255 1 1500

no auto-summary

_________________

ip prefix-list FILTER seq 5 deny 172.16.2.0/30

ip prefix-list FILTER seq 10 deny 172.16.3.0/30

ip prefix-list FILTER seq 15 permit 0.0.0.0/0 le 32

route-map FILTER permit 10

match ip address prefix-list FILTER

_____________________________________

D EX    172.16.4.0 [170/2576128] via 173.12.1.2, 00:01:43, FastEthernet1/0

D EX    172.16.5.0 [170/2576128] via 173.12.1.2, 00:01:43, FastEthernet1/0

D EX    172.16.2.0 [170/2576128] via 173.12.1.2, 00:01:43, FastEthernet1/0

D EX    172.16.3.0 [170/2576128] via 173.12.1.2, 00:01:43, FastEthernet1/0

Rotues are still appering Pleaes let me know if u need any other information.

Thanks,

Zullu

[cadet alain]

Hi,

can you verify these are /30 .

Regards.

Alain

Don't forget to rate helpful posts.

[Zulqadar Ahmad]

Thank you very much issue has been resolved those were /32 lenth ............................ Now those routes(

172.16.2.0/32 and 172.16.3.0/32)

are missing

R10#sh ip route | i 172.16.

     172.16.0.0/32 is subnetted, 2 subnets

D EX    172.16.4.0 [170/2576128] via 173.12.1.2, 00:00:43, FastEthernet1/0

D EX    172.16.5.0 [170/2576128] via 173.12.1.2, 00:00:43, FastEthernet1/0

Regards,

Zulqadar Ahmad