Hello, I have been working on an EIGRP neighboring issue for 2 days but I am stuck getting to the point EIGRP fails. Two sites are connected by 3925 running IOS 15.1(3)T but the first one was running fine on 15.0(1)M3. It looks like after reloading it with 15.1(3)T, it does not neighbors with the second router. Both are connected by their gi0/0 to a MAN connection, 20Mbs. The workaround for now is having a dozen of static route to one site and a redistributed default-gw on the second site. Current AS is 1. Also, the second site neighbors fine with a 3750V2 stack and router 1 neighbors with 4507-R and WAN router.
To test, I created a new AS 5 with simple statments of network 10.0.0.0 and I can see one side trying to neighbor, but the other does not or cannot.
First router, host R3-BRSAO-JU18-05-RTR-01, debug eigrp packets on AS 5 shows:
Jul 7 20:14:51.191 gmt: AS 5, Flags 0x0:(NULL), Seq 0/0 interfaceQ 0/0 iidbQ un/rely 0/0
Jul 7 20:14:51.555 gmt: EIGRP: Sending HELLO on GigabitEthernet0/1
Jul 7 20:14:51.555 gmt: AS 5, Flags 0x0:(NULL), Seq 0/0 interfaceQ 0/0 iidbQ un/rely 0/0
Jul 7 20:14:51.623 gmt: EIGRP: Received HELLO on GigabitEthernet0/2 nbr 10.21.252.2
Jul 7 20:14:51.623 gmt: AS 1, Flags 0x0:(NULL), Seq 0/0 interfaceQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/0
Jul 7 20:14:52.207 gmt: EIGRP: Sending HELLO on GigabitEthernet0/2
Jul 7 20:14:52.207 gmt: AS 5, Flags 0x0:(NULL), Seq 0/0 interfaceQ 0/0 iidbQ un/rely 0/0
Jul 7 20:14:52.635 gmt: EIGRP: Received UPDATE on GigabitEthernet0/0 nbr 10.22.31.18
Jul 7 20:14:52.635 gmt: AS 5, Flags 0x1:(INIT), Seq 8/0 interfaceQ 0/0
Jul 7 20:14:52.635 gmt: EIGRP: Neighbor(10.22.31.18) not yet found
Jul 7 20:14:52.639 gmt: EIGRP: Sending HELLO on Loopback0
Jul 7 20:14:52.639 gmt: AS 5, Flags 0x0:(NULL), Seq 0/0 interfaceQ 0/0 iidbQ un/rely 0/0
Jul 7 20:14:52.639 gmt: EIGRP: Received HELLO on Loopback0 nbr 10.163.32.130
Jul 7 20:14:52.639 gmt: AS 5, Flags 0x0:(NULL), Seq 0/0 interfaceQ 0/0
Jul 7 20:14:52.639 gmt: EIGRP: Packet from ourselves ignored
Jul 7 20:14:52.691 gmt: EIGRP: Received UPDATE on GigabitEthernet0/0 nbr 10.22.31.18
Jul 7 20:14:52.691 gmt: AS 1, Flags 0x1:(INIT), Seq 1484/0 interfaceQ 0/0
Jul 7 20:14:52.691 gmt: EIGRP: Neighbor(10.22.31.18) not yet found
Jul 7 20:14:52.959 gmt: EIGRP: Sending HELLO on GigabitEthernet0/2
Second router, host R3-BRSAO-CE21-04-RTR-01, on AS 5 shows:
Jul 7 23:17:17.520: AS 5, Flags 0x0:(NULL), Seq 0/0 interfaceQ 0/0 iidbQ un/rely 0/0
Jul 7 23:17:17.684: EIGRP: Sending HELLO on Loopback0
Jul 7 23:17:17.684: AS 5, Flags 0x0:(NULL), Seq 0/0 interfaceQ 0/0 iidbQ un/rely 0/0
Jul 7 23:17:17.684: EIGRP: Received HELLO on Loopback0 nbr 10.163.32.177
Jul 7 23:17:17.684: AS 5, Flags 0x0:(NULL), Seq 0/0 interfaceQ 0/0
Jul 7 23:17:17.684: EIGRP: Packet from ourselves ignored
Jul 7 23:17:17.988: EIGRP: Received HELLO on GigabitEthernet0/1 nbr 10.22.31.22
Jul 7 23:17:17.988: AS 1, Flags 0x0:(NULL), Seq 0/0 interfaceQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/0
Jul 7 23:17:18.572: EIGRP: Sending HELLO on GigabitEthernet0/2
Jul 7 23:17:18.572: AS 5, Flags 0x0:(NULL), Seq 0/0 interfaceQ 0/0 iidbQ un/rely 0/0
Jul 7 23:17:19.268: EIGRP: Sending UPDATE on GigabitEthernet0/0 nbr 10.22.31.17, retry 9, RTO 5000 tid 0
Site 1, JK, gi0/0 is 10.22.31.17 and site 2, CE, gi0/0 is 10.22.31.18
Does anyone knows recommend more troubleshooting information for this? I can retry falling back to previous IOS. This same router, neighbors with a 3rd 3925 at local network, over gi0/2/0 running same IOS version, 15.1(3)T without any problem.
