Solved: Quick EIGRP quirk

Ricky Sandhu · ‎02-10-2012

Hey guys, quick EIGRP question for ya. I am still brushing up on my EIGRP so my appologies if this is just a common sense question.

I have a hub and spoke network with DMVPN connectivity with 2 hubs (Hub A and Hub B) and approx. 60 spokes.

Each of these spokes only connects to Hub A (for now) via their local Tunnel0 interface however I have 1 spoke (Spoke X) which also connects to Hub B (simultaneously) over it's local Tunnel1 interface.

At the data center, Hub A and Hub B, each having it's own public interface, also connect to each other via a common switch (for failover reasons).

Hub B knows all of its routes to the spokes via Hub A i.e. through Hub B's interface (GigE0/2) connecting to the switch.

However there are 4-5 spoke routes it is learning via Spoke X since X connects to Hub B (as explained above).

How can I fix this without having to put a static route statement in Hub B to point it to GigE0/2 for those spokes?

Thanks in advance

viswamin · ‎02-10-2012

if any routes are learned via spoke. you can configure the spoke as a "STUB NETWORK" so that it does not form a transit path for any of the routes.

-Vijay

View solution in original post

Dan-Ciprian Cicioiu · ‎02-10-2012

Hi Ricky,

If I understood well you have 59 spokes connected to HUBA and 1 spoke connected to HUBA and HUBB

If this issue apears only to some spokes, I belive that you have some filtering in place on HubA to HubB or on B from A, or

some summarization of those spokes on HubA on the interface to Hub B or some metric offset set for this spokes.

Can you post "show ip eigrp topology SPOKE_LEARND_VIA_SPOKE_X" on HubB.

Also it would be helpfull to the the eigrp config of the Hubs with interface between the hubs config

Dan

Ricky Sandhu · ‎02-10-2012

Hi Dan, here you. Please let me know if you need more information. I just took over this position from a previous network engineer that left the company. Just tring to clean up the mess

______________________________________________________________________________

***HUB B IP route statement for INCORRECTLY learned route and the EIGRP top***

______________________________________________________________________________

HUB-B#sh ip route 172.18.2.1

Routing entry for 172.18.2.0/24

Known via "eigrp 1", distance 90, metric 17920256, type internal

Redistributing via nhrp, eigrp 1

Last update from 10.10.201.27 on Tunnel0, 11:30:06 ago

Routing Descriptor Blocks:

* 10.10.201.27, from 10.10.201.27, 11:30:06 ago, via Tunnel0

Route metric is 17920256, traffic share count is 1

Total delay is 600010 microseconds, minimum bandwidth is 1000 Kbit

Reliability 255/255, minimum MTU 1400 bytes

Loading 255/255, Hops 3

HUB-B#sh ip eigrp topology 172.18.2.0/24

EIGRP-IPv4 Topology Entry for AS(1)/ID(1.1.1.2) for 172.18.2.0/24

State is Passive, Query origin flag is 1, 4 Successor(s), FD is 17920256

Descriptor Blocks:

10.10.201.27 (Tunnel0), from 10.10.201.27, Send flag is 0x0

Composite metric is (17920256/15360256), route is Internal

Vector metric:

Minimum bandwidth is 1000 Kbit

Total delay is 600010 microseconds

Reliability is 255/255

Load is 255/255

Minimum MTU is 1400

Hop count is 3

!

______________________________________________________________________________

***HUB B IP route statement for a CORRECTLY learned route***

______________________________________________________________________________

HUB-B#sh ip route 172.18.24.1

Routing entry for 172.18.24.0/24

Known via "eigrp 1", distance 90, metric 2560512, type internal

Redistributing via nhrp, eigrp 1

Last update from 172.18.123.2 on GigabitEthernet0/2, 11:29:42 ago

Routing Descriptor Blocks:

* 172.18.123.2, from 172.18.123.2, 11:29:42 ago, via GigabitEthernet0/2

Route metric is 2560512, traffic share count is 1

Total delay is 50020 microseconds, minimum bandwidth is 2000 Kbit

Reliability 255/255, minimum MTU 1400 bytes

Loading 255/255, Hops 2

!

________________________________________

***HUB B EIGRP Config snippet***

________________________________________

!

interface Tunnel0

bandwidth 1000

ip address 10.10.201.1 255.255.255.0

no ip redirects

ip accounting output-packets

ip mtu 1400

no ip next-hop-self eigrp 1

ip nhrp authentication Trow!

ip nhrp map multicast dynamic

ip nhrp network-id 201

ip nhrp holdtime 600

no ip split-horizon eigrp 1

tunnel source GigabitEthernet0/0

tunnel mode gre multipoint

tunnel key 201

tunnel protection ipsec profile profile1

!

interface Tunnel2

ip address 10.10.202.1 255.255.255.0

no ip redirects

ip mtu 1400

no ip next-hop-self eigrp 1

ip nhrp authentication Trow!

ip nhrp map multicast dynamic

ip nhrp network-id 202

ip nhrp holdtime 600

ip nhrp registration no-unique

no ip split-horizon eigrp 1

tunnel source GigabitEthernet0/0

tunnel mode gre multipoint

tunnel key 202

tunnel protection ipsec profile profile2

!

interface GigabitEthernet0/0

description OUTSIDE

ip address ***.***.***.*** 255.255.255.240

ip access-group BLOCK in

no ip route-cache cef

no ip route-cache

duplex auto

speed auto

!

interface GigabitEthernet0/2

description Switch-G2/0/24

ip address 172.18.123.3 255.255.255.0

duplex auto

speed auto

standby 123 ip 172.18.123.1

standby 123 priority 90

!

router eigrp 1

network 1.1.1.2 0.0.0.0

network 10.10.201.0 0.0.0.255

network 10.10.202.0 0.0.0.255

network 172.18.123.0 0.0.0.255

redistribute static route-map STATIC-TO-EIGRP

!

ip forward-protocol nd

!

ip route 0.0.0.0 0.0.0.0 ***.***.***.***

ip route 172.18.120.0 255.255.255.0 172.18.123.250

ip route 172.18.121.0 255.255.255.0 172.18.123.250

ip route 172.18.122.0 255.255.255.0 172.18.123.250

!

ip access-list standard STATIC-TO-EIGRP

permit 172.18.120.0 0.0.0.255

permit 172.18.121.0 0.0.0.255

permit 172.18.122.0 0.0.0.255

!

access-list 23 permit 172.18.0.0 0.0.255.255

!

route-map STATIC-TO-EIGRP permit 10

match ip address STATIC-TO-EIGRP

!

________________________________________

***HUB A EIGRP Config snippet***

________________________________________

interface Tunnel0

bandwidth 2000

ip address 10.10.200.1 255.255.255.0

no ip redirects

ip accounting output-packets

ip mtu 1400

no ip next-hop-self eigrp 1

ip nhrp authentication Trow!

ip nhrp map multicast dynamic

ip nhrp network-id 200

ip nhrp holdtime 600

no ip split-horizon eigrp 1

tunnel source GigabitEthernet0/0

tunnel mode gre multipoint

tunnel key 200

tunnel protection ipsec profile Profile1

!

interface GigabitEthernet0/0

description OUTSIDE

ip address ***.***.***.*** 255.255.255.240

ip access-group BLOCK in

duplex auto

speed auto

!

interface GigabitEthernet0/1

description int

no ip address

shutdown

duplex auto

speed auto

!

interface GigabitEthernet0/2

description Switch-G1/0/24

ip address 172.18.123.2 255.255.255.0

duplex auto

speed auto

standby 123 ip 172.18.123.1

standby 123 priority 110

standby 123 preempt

standby 123 track 1 decrement 30

!

router eigrp 1

network 1.1.1.1 0.0.0.0

network 10.10.200.0 0.0.0.255

network 172.18.123.0 0.0.0.255

redistribute static route-map STATIC-TO-EIGRP

!

ip forward-protocol nd

!

ip http server

ip http access-class 23

ip http authentication local

ip http secure-server

ip http timeout-policy idle 60 life 86400 requests 10000

!

ip route 0.0.0.0 0.0.0.0 ***.***.***.***

ip route 10.0.10.0 255.255.255.0 172.18.123.250

ip route 10.10.5.0 255.255.255.0 172.18.123.250

ip route 10.102.154.0 255.255.255.0 172.18.123.250

ip route 172.18.0.0 255.255.255.0 172.18.123.250

ip route 172.18.4.0 255.255.255.0 172.18.23.250

ip route 172.18.10.0 255.255.255.0 10.10.200.19

ip route 172.18.11.0 255.255.255.0 172.18.123.250

ip route 172.18.70.0 255.255.255.0 172.18.123.250

ip route 172.18.120.0 255.255.255.0 172.18.123.250

ip route 172.18.121.0 255.255.255.0 172.18.123.250

ip route 172.18.122.0 255.255.255.0 172.18.123.250

ip route 172.18.168.0 255.255.255.0 172.18.123.250

ip route 192.168.2.0 255.255.255.0 172.18.123.250

ip route 192.168.220.0 255.255.255.0 172.18.123.4

ip route 192.168.254.0 255.255.255.0 172.18.123.250

!

ip access-list standard STATIC-TO-EIGRP

permit 172.18.120.0 0.0.0.255

permit 172.18.121.0 0.0.0.255

permit 172.18.122.0 0.0.0.255

permit 172.18.11.0 0.0.0.255

permit 10.102.154.0 0.0.0.255

permit 10.120.120.0 0.0.0.255

permit 192.168.254.0 0.0.0.255

permit 10.10.5.0 0.0.0.255

!

access-list 5 permit 172.18.120.0 0.0.0.255

access-list 23 permit 172.18.0.0 0.0.255.255

!

route-map STATIC-TO-EIGRP permit 10

match ip address STATIC-TO-EIGRP

!

viswamin · ‎02-10-2012

if any routes are learned via spoke. you can configure the spoke as a "STUB NETWORK" so that it does not form a transit path for any of the routes.

-Vijay

Dan-Ciprian Cicioiu · ‎02-10-2012

Yes this is a very nice solution,Vijay

But if there is any fitering between A and B won't solve it.

Dan

Ricky Sandhu · ‎02-10-2012

Hi Vijay, if I add the Eigrp Stub command in the EIGRP portion of the config on a live router, that would've cause a connection drop would it?

viswamin · ‎02-10-2012

Yes. When you configure the spoke as STUB, then the neighborship goes down and comes back..

If you dont want the neighborship, then we can filter the route using prefix list ..

May be Experts would have some more thoughts as I'm still learning ....

-Vijay.

Ricky Sandhu · ‎02-10-2012

Thanks Vijay. EIGRP Stub command seemed to have fixed the issue.