EIGRP and BGP routes not working as should

Unanswered Question
Dec 5th, 2008

I'm new to BGP and only have a little experience in EIGRP.

I am coming into a network that is already setup but I am trying to add new subnets and the routing is screwing up.

We have a core router (4507R-E) and it's routing table looks like:

router eigrp 101

network 10.0.0.0

network 192.168.15.0

network 192.168.32.0

network 192.168.33.0

network 192.168.34.0

network 192.168.35.0

network 192.168.36.0

network 192.168.50.0

network 192.168.52.0

network 192.168.187.0

no eigrp log-neighbor-changes

no auto-summary

!

ip route 0.0.0.0 0.0.0.0 192.168.187.99

ip route 192.168.187.0 255.255.255.0 192.168.187.99

ip route 192.168.198.0 255.255.255.0 192.168.187.99

ip route 192.168.199.0 255.255.255.0 192.168.187.99

We also have a MPLS router (2851) and it's routing is setup as:

router eigrp 101

redistribute bgp 64803 metric 10000 10 255 1 1500

network 192.168.187.0

no auto-summary

!

router bgp 64803

no synchronization

bgp log-neighbor-changes

network 192.168.12.0

network 192.168.15.0

network 192.168.32.0

network 192.168.33.0

network 192.168.34.0

network 192.168.35.0

network 192.168.36.0

network 192.168.50.0

network 192.168.52.0

network 192.168.187.0

network 192.168.198.0

neighbor 64.129.251.57 remote-as 4323

no auto-summary

!

ip forward-protocol nd

ip route 0.0.0.0 0.0.0.0 192.168.187.99

ip route 192.168.198.0 255.255.255.0 192.168.187.99

I am trying to add the 192.168.52.0 network.

when I do a sh IP route on the 4507 is shows the 192.168.52.0 network as 'C 192.168.52.0/24 is directly connected, Vlan52'

when I do a 'sh ip route' on the 2821 I get 'B 192.168.52.0/24 [20/0] via 64.129.100.57, 1w4d'. That is our MPLS address

The 2821 and the 4507 are connected so it should say 'D 192.168.53.0/24 [90/3072] via 192.168.187.1, 7w0d, GigabitEthernet0/0', but i'm not getting that.

all the other networks are correct:

D 192.168.34.0/24 [90/3072] via 192.168.187.1, 7w0d, GigabitEthernet0/0

D 192.168.50.0/24 [90/3072] via 192.168.187.1, 7w0d, GigabitEthernet0/0

D 192.168.35.0/24 [90/3072] via 192.168.187.1, 7w0d, GigabitEthernet0/0

...etc

, but when I try to add a new network to eigrp 101 on the 4507 it wants to go through BGP. Any clue why?

I have this problem too.
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Jon Marshall Fri, 12/05/2008 - 13:09

Are you sure that 192.168.52.0 is not being advertised from another of your sites via BGP.

On the 2821

2821# sh ip bgp neigh 64.129.251.57 received routes | include 192.168.52

this should show you if you are receiving this route from your BGP peer.

Other than that could you post output of "sh ip route" from 2821 and 4500.

Jon

the_crooked_toe Fri, 12/05/2008 - 13:21

Hey Jon,

I did the sh ip bgp neigh 64.129.251.57 received routes | include 192.168.52 but it returned nothing. It should only be coming from the 4507

GDM-4507R#sh ip rou

Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2

i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2

ia - IS-IS inter area, * - candidate default, U - per-user static route

o - ODR, P - periodic downloaded static route

Gateway of last resort is 192.168.187.99 to network 0.0.0.0

D EX 192.168.28.0/24 [170/258816] via 192.168.187.252, 7w0d, Vlan1

D EX 192.168.13.0/24 [170/258816] via 192.168.187.252, 3w3d, Vlan1

C 192.168.15.0/24 is directly connected, Vlan15

64.0.0.0/30 is subnetted, 4 subnets

D EX 64.129.251.56 [170/1767168] via 192.168.187.254, 1w4d, Vlan1

D EX 64.129.251.60 [170/258816] via 192.168.187.252, 7w0d, Vlan1

D EX 64.129.251.72 [170/258816] via 192.168.187.252, 7w0d, Vlan1

D EX 64.129.251.76 [170/258816] via 192.168.187.252, 3w3d, Vlan1

D 192.168.128.0/24 [90/1762048] via 192.168.187.254, 4d04h, Vlan1

S 192.168.198.0/24 [1/0] via 192.168.187.99

S 192.168.199.0/24 [1/0] via 192.168.187.99

10.0.0.0/24 is subnetted, 21 subnets

C 10.110.100.0 is directly connected, Vlan100

C 10.110.101.0 is directly connected, Vlan101

C 10.110.115.0 is directly connected, Vlan115

D 10.150.213.0 [90/3181312] via 192.168.187.254, 1d02h, Vlan1

D EX 10.150.210.0 [170/258816] via 192.168.187.252, 1d02h, Vlan1

D 10.150.201.0 [90/3181312] via 192.168.187.254, 2d08h, Vlan1

C 10.110.5.0 is directly connected, Vlan5

C 10.110.2.0 is directly connected, Vlan2

D EX 10.110.232.0 [170/258816] via 192.168.187.252, 1d03h, Vlan1

D EX 10.110.233.0 [170/258816] via 192.168.187.252, 1d03h, Vlan1

D 10.150.10.0 [90/3181312] via 192.168.187.254, 2d08h, Vlan1

D 10.150.5.0 [90/3178752] via 192.168.187.254, 2d08h, Vlan1

D 10.150.2.0 [90/3181312] via 192.168.187.254, 2d08h, Vlan1

C 10.110.201.0 is directly connected, Vlan201

C 10.110.213.0 is directly connected, Vlan213

D EX 10.10.201.0 [170/258816] via 192.168.187.252, 1d02h, Vlan1

D 10.20.201.0 [90/1764864] via 192.168.187.254, 1w4d, Vlan1

C 10.110.132.0 is directly connected, Vlan132

C 10.110.133.0 is directly connected, Vlan133

D 10.150.110.0 [90/3181312] via 192.168.187.254, 2d08h, Vlan1

D 10.150.100.0 [90/3181312] via 192.168.187.254, 2d08h, Vlan1

D 192.168.113.0/24 [90/1762048] via 192.168.187.254, 1w4d, Vlan1

C 192.168.36.0/24 is directly connected, Vlan36

C 192.168.53.0/24 is directly connected, Vlan53

C 192.168.52.0/24 is directly connected, Vlan52

C 192.168.187.0/24 is directly connected, Vlan1

C 192.168.34.0/24 is directly connected, Vlan34

C 192.168.50.0/24 is directly connected, Vlan50

C 192.168.35.0/24 is directly connected, Vlan35

D 192.168.118.0/24 [90/1762048] via 192.168.187.254, 1w4d, Vlan1

D EX 192.168.253.0/24 [170/258816] via 192.168.187.252, 1w4d, Vlan1

C 192.168.32.0/24 is directly connected, Vlan32

D EX 192.168.18.0/24 [170/258816] via 192.168.187.252, 7w0d, Vlan1

C 192.168.33.0/24 is directly connected, Vlan33

S* 0.0.0.0/0 [1/0] via 192.168.187.99

the_crooked_toe Fri, 12/05/2008 - 13:21

LOU-GDM-TWC-MPLS#sh ip rou

Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2

i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2

ia - IS-IS inter area, * - candidate default, U - per-user static route

o - ODR, P - periodic downloaded static route

Gateway of last resort is 192.168.187.99 to network 0.0.0.0

B 192.168.28.0/24 [20/0] via 64.129.251.57, 7w0d

B 192.168.13.0/24 [20/0] via 64.129.251.57, 3w3d

D 192.168.15.0/24 [90/3072] via 192.168.187.1, 7w0d, GigabitEthernet0/0

64.0.0.0/30 is subnetted, 4 subnets

C 64.129.251.56 is directly connected, GigabitEthernet0/1

B 64.129.251.60 [20/0] via 64.129.251.57, 7w0d

B 64.129.251.72 [20/0] via 64.129.251.57, 7w0d

B 64.129.251.76 [20/0] via 64.129.251.57, 3w3d

B 192.168.128.0/24 [20/0] via 64.129.251.57, 4d04h

S 192.168.198.0/24 [1/0] via 192.168.187.99

10.0.0.0/24 is subnetted, 21 subnets

B 10.110.100.0 [20/0] via 64.129.251.57, 1w2d

B 10.110.101.0 [20/0] via 64.129.251.57, 1w2d

B 10.110.115.0 [20/0] via 64.129.251.57, 1w4d

B 10.150.213.0 [20/0] via 64.129.251.57, 1d02h

B 10.150.210.0 [20/0] via 64.129.251.57, 2d08h

B 10.150.201.0 [20/0] via 64.129.251.57, 2d08h

B 10.110.5.0 [20/0] via 64.129.251.57, 3d02h

B 10.110.2.0 [20/0] via 64.129.251.57, 1w4d

B 10.110.232.0 [20/0] via 64.129.251.57, 1w4d

B 10.110.233.0 [20/0] via 64.129.251.57, 1w4d

B 10.150.10.0 [20/0] via 64.129.251.57, 2d08h

B 10.150.5.0 [20/0] via 64.129.251.57, 2d08h

B 10.150.2.0 [20/0] via 64.129.251.57, 2d08h

B 10.110.201.0 [20/0] via 64.129.251.57, 1d02h

B 10.110.213.0 [20/0] via 64.129.251.57, 1d02h

B 10.10.201.0 [20/0] via 64.129.251.57, 3w3d

B 10.20.201.0 [20/0] via 64.129.251.57, 1w4d

B 10.110.132.0 [20/0] via 64.129.251.57, 1w4d

B 10.110.133.0 [20/0] via 64.129.251.57, 1w4d

B 10.150.110.0 [20/0] via 64.129.251.57, 2d08h

B 10.150.100.0 [20/0] via 64.129.251.57, 2d08h

B 192.168.113.0/24 [20/0] via 64.129.251.57, 1w4d

D 192.168.36.0/24 [90/3072] via 192.168.187.1, 7w0d, GigabitEthernet0/0

B 192.168.52.0/24 [20/0] via 64.129.251.57, 1w4d

C 192.168.187.0/24 is directly connected, GigabitEthernet0/0

D 192.168.34.0/24 [90/3072] via 192.168.187.1, 7w0d, GigabitEthernet0/0

D 192.168.50.0/24 [90/3072] via 192.168.187.1, 7w0d, GigabitEthernet0/0

D 192.168.35.0/24 [90/3072] via 192.168.187.1, 7w0d, GigabitEthernet0/0

B 192.168.118.0/24 [20/0] via 64.129.251.57, 1w4d

B 192.168.253.0/24 [20/0] via 64.129.251.57, 1w4d

D 192.168.32.0/24 [90/3072] via 192.168.187.1, 7w0d, GigabitEthernet0/0

B 192.168.18.0/24 [20/0] via 64.129.251.57, 7w0d

D 192.168.33.0/24 [90/3072] via 192.168.187.1, 7w0d, GigabitEthernet0/0

S* 0.0.0.0/0 [1/0] via 192.168.187.99

thotsaphon Fri, 12/05/2008 - 13:15

hi Kendrick,

2821 is working correctly. Because EBGP has a better administrative distance than EIGRP.

"The 2821 and the 4507 are connected so it should say 'D 192.168.53.0/24 [90/3072] via 192.168.187.1, 7w0d, GigabitEthernet0/0', but i'm not getting that."

You mean, D 192.168.52.0/24 [90/3072] via 192.168.187.1, 7w0d, GigabitEthernet0/0'. right?

I'm not sure why 2821 has learnt 192.168.52.0 via BGP. Is there an overlapping network?

I would be good if you provide us to see what the network topology looks like.

Toshi

the_crooked_toe Fri, 12/05/2008 - 13:25

Attached is the network topology. some of the ip addresses are different. The bottom left corner is the core router and the MPLS router I'm trying to get configured properly

Giuseppe Larosa Fri, 12/05/2008 - 13:23

Hello,

>> when I do a 'sh ip route' on the 2821 I get 'B 192.168.52.0/24 [20/0] via 64.129.100.57, >> 1w4d'.

it means that since almost two weeks ago anothe site is advertising the 192.168.52.0/24 IP subnet.

the C2821 MPLS router cannot start to advertise the prefix received in EIGRP because that prefix is already installed in the routing table as an eBGP route.

Verify in in a remote site there is a duplicated subnet or a wrong static route redistribution into BGP

to check this you can on C2821

sh ip bgp 192.168.52.0

if the last letter rightmost is an i there is a network command on the remote router in its BGP config if it is a ? there is a redistribution into BGP

You need to access the remote router in any case.

Hope to help

Giuseppe

the_crooked_toe Fri, 12/05/2008 - 13:28

i can guarentee that route is no where else on the network. I can try any subnet and they are all not working properly. If you look at the sh ip routes on my previous posts, those 10.110. networks should say connected via EIGRP to 192.168.187.1. its like every subnet is not working correctly.

the_crooked_toe Fri, 12/05/2008 - 13:30

LOU-GDM-TWC-MPLS#sh ip bgp 192.168.52.0

BGP routing table entry for 192.168.52.0/24, version 6534

Paths: (1 available, best #1, table Default-IP-Routing-Table)

Not advertised to any peer

4323 4323

64.129.251.57 from 64.129.251.57 (64.129.251.57)

Origin incomplete, localpref 100, valid, external, best

Community: 283312179 283312629 283313194 283314630 283314633 4266460202 4266524675 4266590209 4266655945

Extended Community: RT:64803:100000

Jon Marshall Fri, 12/05/2008 - 13:44

Can you post "sh ip bgp 192.168.50.0" and the output of "sh ip bgp" from 2821.

Jon

the_crooked_toe Fri, 12/05/2008 - 13:47

this is all done from the 2821

LOU-GDM-TWC-MPLS#sh ip bgp

BGP table version is 6575, local router ID is 192.168.187.252

Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,

r RIB-failure, S Stale

Origin codes: i - IGP, e - EGP, ? - incomplete

Network Next Hop Metric LocPrf Weight Path

r> 0.0.0.0 64.129.251.57 0 4323 4323 ?

*> 10.10.201.0/24 64.129.251.57 0 4323 4323 ?

*> 10.20.201.0/24 64.129.251.57 0 4323 4323 ?

*> 10.110.2.0/24 64.129.251.57 0 4323 4323 ?

*> 10.110.5.0/24 64.129.251.57 0 4323 4323 ?

*> 10.110.100.0/24 64.129.251.57 0 4323 4323 ?

*> 10.110.101.0/24 64.129.251.57 0 4323 4323 ?

*> 10.110.115.0/24 64.129.251.57 0 4323 4323 ?

*> 10.110.132.0/24 64.129.251.57 0 4323 4323 ?

*> 10.110.133.0/24 64.129.251.57 0 4323 4323 ?

*> 10.110.201.0/24 64.129.251.57 0 4323 4323 ?

*> 10.110.213.0/24 64.129.251.57 0 4323 4323 ?

*> 10.110.232.0/24 64.129.251.57 0 4323 4323 ?

*> 10.110.233.0/24 64.129.251.57 0 4323 4323 ?

*> 10.150.2.0/24 64.129.251.57 0 4323 4323 ?

*> 10.150.5.0/24 64.129.251.57 0 4323 4323 ?

*> 10.150.10.0/24 64.129.251.57 0 4323 4323 ?

*> 10.150.100.0/24 64.129.251.57 0 4323 4323 ?

*> 10.150.110.0/24 64.129.251.57 0 4323 4323 ?

*> 10.150.201.0/24 64.129.251.57 0 4323 4323 ?

*> 10.150.210.0/24 64.129.251.57 0 4323 4323 ?

*> 10.150.213.0/24 64.129.251.57 0 4323 4323 ?

r> 64.129.251.56/30 64.129.251.57 0 4323 i

*> 64.129.251.60/30 64.129.251.57 0 4323 i

*> 64.129.251.72/30 64.129.251.57 0 4323 i

*> 64.129.251.76/30 64.129.251.57 0 4323 i

*> 192.168.13.0 64.129.251.57 0 4323 4323 i

*> 192.168.15.0 192.168.187.1 3072 32768 i

*> 192.168.18.0 64.129.251.57 0 4323 4323 i

*> 192.168.28.0 64.129.251.57 0 4323 4323 i

*> 192.168.32.0 192.168.187.1 3072 32768 i

*> 192.168.33.0 192.168.187.1 3072 32768 i

*> 192.168.34.0 192.168.187.1 3072 32768 i

*> 192.168.35.0 192.168.187.1 3072 32768 i

*> 192.168.36.0 192.168.187.1 3072 32768 i

*> 192.168.50.0 192.168.187.1 3072 32768 i

*> 192.168.52.0 64.129.251.57 0 4323 4323 ?

*> 192.168.113.0 64.129.251.57 0 4323 4323 ?

*> 192.168.118.0 64.129.251.57 0 4323 4323 ?

*> 192.168.128.0 64.129.251.57 0 4323 4323 ?

*> 192.168.187.0 0.0.0.0 0 32768 i

*> 192.168.198.0 192.168.187.99 0 32768 i

*> 192.168.253.0 64.129.251.57 0 4323 4323 ?

the_crooked_toe Fri, 12/05/2008 - 13:50

its weird because anything 10.110 should be coming from 192.168.187.1

and anything from 10.150 should be coming from 192.168.187.254

Jon Marshall Fri, 12/05/2008 - 13:51

192.168.50.0 has an origin of IGP which is correct because it was learnt from EIGRP.

But 192.168.52.0 has an origin of incomplete which usually means it has been redistributed into the routing protocol.

Could you "clear ip route 192.168.50.0" on the 2821 and then checkk routing table again. That route is being advertised to the 2821 from somewhere other than the 4500.

Jon

thotsaphon Fri, 12/05/2008 - 13:52

hi Kendrick,

It's weird. I would recommend you to talk to TWC MPLS. You're learning all confusing routes from AS 4323,including AS-PATH prepending via 64.129.251.57.

Toshi

the_crooked_toe Fri, 12/05/2008 - 13:58

well i did a clear ip route 192.168.52.0 and now it's learning from 192.168.187.1, which is great.

but now i'm trying to get the 10.110 network to work. i'm trying to clear those and they keep on repopulating through the MPLS

I guess I will need to give TWC a call. thanks for the help.

Do you think i should just clear out ALL IP routing protocols and just start over once again?

Jon Marshall Fri, 12/05/2008 - 14:03

I think that at sometime as Giuseppe and i said the 192.168.52.0 network was somehow advertised from outside your site to your 2821 router. It's not now by the looks of it so the 182.168.52.0 from the 4500 is used.

I agree with the others, it looks like you are receiving some very funny routes. You need to talk to your ISP.

Jon

Giuseppe Larosa Fri, 12/05/2008 - 13:50

Hello Kendrick,

I would make a call to your MPLS ISP:

you shouldn't receive a BGP update containing an MPLS VPN extended community attribute:

>>Extended Community: RT:64803:100000

I don't think your router should see this: it is part of ISP internal signalling plane.

To be noted there is a chance that with a misconfiguration they joined the routes of two different VPNs if really there is no duplicated subnets in your sites and no redistributions into BGP on other sites' CE routers

(ok may be it has send-community both to you but the route-target should be stripped to a CE node)

Hope to help

Giuseppe

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