Cisco DMVPN - EIGRP Neighbor Issue

[josiah138]

Hi;

I have two Cisco 1921 Routers setup with a DMVPN. The tunnel comes up no problem and the routers exchange a new adjacency. However, the adjacency they form is for the tunnel network (172.16.0.0). On both routers, I have used the following network statements in the AS:

172.16.0.0 (tunnel interface)

x.x.x.x (local subnet)

The routers do not build an adjacency for each side's local subnet, only the the tunnel subnet. So communication obviously fails. If I create a static route on each router to route between local subnets, it only works from Spoke to Hub, not from Hub to spoke.

Why is EIGRP not forming the adjacency for the local subnet behind each router?

Thanks!

[Francesco Molino]

Hi

Can you please share your config?

[josiah138]

Thanks for the reply - here are the configs.

[Francesco Molino]

Sorry it was a crazy day. I'll take a look tomorrow at your configs.
In the mean time, i forgot to ask before, can you please share following outputs on both routers:
- sh ip eigrp neig
- sh ip route

[josiah138]

Thanks Franscesco. Show outputs are attached. As you can see,  neighbors form on the tunnel interface, but EIGRP doesn't exchange routes for the 10.0.0.0 and 192.168.1.0 networks on each side.

Note: I put static routes in to try an achieve this but only the spoke is able to see the hub side. Not the other way around.

[Francesco Molino]

Ok let me test it over the week end with your configs.
By the way, you don't need no next-hop-self on spoke side.

[josiah138]

Thank-you. Yes I do realize that command is not necessary on the spoke. Was just trying everything to make it work.

Thanks again.

[Francesco Molino]

I tested your config and it works good.

My spoke loopback is 10.30.30.1

From HUB:

DMVPN is up

Interface: Tunnel0, IPv4 NHRP Details
Type:Hub, NHRP Peers:1,

# Ent Peer NBMA Addr Peer Tunnel Add State UpDn Tm Attrb
----- --------------- --------------- ----- -------- -----
1 200.200.200.2 172.16.0.2 UP 00:01:18 D

EIGRP is up

EIGRP-IPv4 Neighbors for AS(123)
H Address Interface Hold Uptime SRTT RTO Q Seq
(sec) (ms) Cnt Num
0 172.16.0.2 Tu0 11 00:01:50 6 100 0 3

My RIB has learned a subnet from EIGRP

HUB-RTR#sh ip route eigrp
Codes: L - local, 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, H - NHRP, l - LISP
a - application route
+ - replicated route, % - next hop override

Gateway of last resort is 100.100.100.1 to network 0.0.0.0

10.0.0.0/32 is subnetted, 2 subnets
D 10.30.30.1 [90/640000] via 172.16.0.2, 00:02:12, Tunnel0

I noticed you have the same loopback on both side when reading the config you've attached.

Can you change it on your spoke with 10.10.10.2 instead of 10.10.10.1

[josiah138]

Yeah... I have this same config at about 6 other sites and it works fine. I tried your suggestion of changing IP address of Loopback. Unfortunately, no change... Any other thoughts?

Thanks for your help thus far.

Brian.

[Francesco Molino]

Loopback wasn't causing the issue, I just said because I guess it was a typo error.
Can you do a debug eigrp and clear ip eigrp neighbor ?
Share the output of debug please.

[josiah138]

Debug output attached. A neighbor forms, however the issue is that EIGRP is not sharing routes to the local subnet on each side. The 172.16.0.0 network is the tunnel network.

[Francesco Molino]

Missing some info here. Run please:
- debug eigrp packet verbose

[josiah138]

New debug attached. Thank you.

[Francesco Molino]

I don't see any topology exchange and also multicast communication isn't working.
Have your remove no ip next-hop on hub and no ip next-hop + no ip split on spoke?
Can you share full updated config and your design please (quick sketch is enough)?

[josiah138]

I tried removing the suggested commands. Still doesn't work. I've attached updated configs.

As far as design, very simple. Both sites have a Cisco 1921 connected to a cable modem in bridge mode.

Thank you.