EIGRP Router ID - not using loopback

wave

Hi there,

I'm doing an EIGRP lab right now and I have a loopback on R1 of 200.1.1.1. R1 and R2 are connected via serial connection on the 172.16.12.0/24 network and the neighborship has been formed, routers have been exchanged...

R2 sees R1's router-id as 172.16.12.1 instead of the loopback address 200.1.1.1.

Everything I've read has told me that if the RID is not explicitly configured, EIGRP will select the highest loopback address first for the RID. If there is no loopback then it will select the highest IP address on an up/up interface.

Has anyone else come across this?

EDIT: I think I misinterpreted this...

I just did a:

R1#sh ip eigrp topology
IP-EIGRP Topology Table for AS(1)/ID(200.1.1.1)

Then on R2:

R2#sh ip eigrp neighbors
IP-EIGRP neighbors for process 1
H Address Interface Hold Uptime SRTT RTO Q Seq (sec) (ms) Cnt Num
0 172.16.12.1 Se1/0 13 00:12:11 45 2280 0 6

I had always thought "Address" was the RID, but it must be the IP the neighbor is using to communicate.

SubnetZero

You got it!

In Cisco IOS Software Release 12.1 and later, the show ip eigrp topology command shows the RID.

With OSPF you can see your neighbors RID with the "show ip ospf neighbors" command under Neighbor ID

R1(config-if)#do sh ip o n
Neighbor ID Pri State Dead Time Address Interface
2.2.2.2 1 FULL/DR 00:00:38 192.168.100.2 FastEthernet0/0

Cheers!