DMVPN, reconnect every 2-3 minutes

NETWORKING SOLUTIONS
1

Hello,
I am trying to build DMVPN between Cisco IR1101 (hub) and Teltonika RUT955 07.06.18 (spoke)

I got a problem like this - DMVPN reconnects every ~2 minutes

Perhaps this behavior is due to the fact that they are not being NHRP registering.

In Cisco IR1101 (192.168.23.1) NHRP registrations successfull:
image

image
image1144×222 9.62 KB

172.16.45.1 - wan ip Hub Cisco IR1101
172.16.45.5 - wan ip Spoke Teltonika

But in log on RUT955 (192.168.23.2) I can see like this:
Tue Apr 8 13:11:31 2025 daemon.debug nhrpd[2374]: [PTQ80-8JY6C] Send Registration-Request(3) 192.168.23.2 → 192.168.23.1
Tue Apr 8 13:12:35 2025 daemon.debug nhrpd[2374]: [Z7K3A-GSQPT] NHS: Register 192.168.23.2 → 192.168.23.1 (timeout 2)
Tue Apr 8 13:12:35 2025 daemon.debug nhrpd[2374]: [G1PDS-NV9WX] NHS: cisco authentification UGV
Tue Apr 8 13:12:35 2025 daemon.debug nhrpd[2374]: [J5RTA-858YQ] nhrp_auth_push: AUTH LEN 3
Tue Apr 8 13:12:35 2025 daemon.debug nhrpd[2374]: [PTQ80-8JY6C] Send Registration-Request(3) 192.168.23.2 → 192.168.23.1
Tue Apr 8 13:12:37 2025 daemon.debug nhrpd[2374]: [Z7K3A-GSQPT] NHS: Register 192.168.23.2 → 192.168.23.1 (timeout 4)
Tue Apr 8 13:12:37 2025 daemon.debug nhrpd[2374]: [G1PDS-NV9WX] NHS: cisco authentification UGV
Tue Apr 8 13:12:37 2025 daemon.debug nhrpd[2374]: [J5RTA-858YQ] nhrp_auth_push: AUTH LEN 3
Tue Apr 8 13:12:37 2025 daemon.debug nhrpd[2374]: [PTQ80-8JY6C] Send Registration-Request(3) 192.168.23.2 → 192.168.23.1
Tue Apr 8 13:12:41 2025 daemon.debug nhrpd[2374]: [Z7K3A-GSQPT] NHS: Register 192.168.23.2 → 192.168.23.1 (timeout 8)
Tue Apr 8 13:12:41 2025 daemon.debug nhrpd[2374]: [G1PDS-NV9WX] NHS: cisco authentification UGV
Tue Apr 8 13:12:41 2025 daemon.debug nhrpd[2374]: [J5RTA-858YQ] nhrp_auth_push: AUTH LEN 3
Tue Apr 8 13:12:41 2025 daemon.debug nhrpd[2374]: [PTQ80-8JY6C] Send Registration-Request(3) 192.168.23.2 → 192.168.23.1
Tue Apr 8 13:12:49 2025 daemon.debug nhrpd[2374]: [Z7K3A-GSQPT] NHS: Register 192.168.23.2 → 192.168.23.1 (timeout 16)
Tue Apr 8 13:12:49 2025 daemon.debug nhrpd[2374]: [G1PDS-NV9WX] NHS: cisco authentification UGV
Tue Apr 8 13:12:49 2025 daemon.debug nhrpd[2374]: [J5RTA-858YQ] nhrp_auth_push: AUTH LEN 3
Tue Apr 8 13:12:49 2025 daemon.debug nhrpd[2374]: [PTQ80-8JY6C] Send Registration-Request(3) 192.168.23.2 → 192.168.23.1
Tue Apr 8 13:13:05 2025 daemon.debug nhrpd[2374]: [Z7K3A-GSQPT] NHS: Register 192.168.23.2 → 192.168.23.1 (timeout 32)
Tue Apr 8 13:13:05 2025 daemon.debug nhrpd[2374]: [G1PDS-NV9WX] NHS: cisco authentification UGV
Tue Apr 8 13:13:05 2025 daemon.debug nhrpd[2374]: [J5RTA-858YQ] nhrp_auth_push: AUTH LEN 3
Tue Apr 8 13:13:05 2025 daemon.debug nhrpd[2374]: [PTQ80-8JY6C] Send Registration-Request(3) 192.168.23.2 → 192.168.23.1
Tue Apr 8 13:13:37 2025 daemon.debug nhrpd[2374]: [Z7K3A-GSQPT] NHS: Register 192.168.23.2 → 192.168.23.1 (timeout 64)
Tue Apr 8 13:13:37 2025 daemon.debug nhrpd[2374]: [G1PDS-NV9WX] NHS: cisco authentification UGV
Tue Apr 8 13:13:37 2025 daemon.debug nhrpd[2374]: [J5RTA-858YQ] nhrp_auth_push: AUTH LEN 3
Tue Apr 8 13:13:37 2025 daemon.debug nhrpd[2374]: [PTQ80-8JY6C] Send Registration-Request(3) 192.168.23.2 → 192.168.23.1
…
tcpdump on wan int RUT955:
14:24:05.746898 IP 172.16.45.5 > 172.16.45.1: GREv0, key=0x4d2, length 111: gre-proto-0x2001
14:24:05.751043 IP 172.16.45.1 > 172.16.45.5: GREv0, key=0x4d2, length 131: gre-proto-0x2001
14:24:07.758306 IP 172.16.45.5 > 172.16.45.1: GREv0, key=0x4d2, length 111: gre-proto-0x2001
14:24:07.762317 IP 172.16.45.1 > 172.16.45.5: GREv0, key=0x4d2, length 131: gre-proto-0x2001
14:24:11.770805 IP 172.16.45.5 > 172.16.45.1: GREv0, key=0x4d2, length 111: gre-proto-0x2001
14:24:11.773071 IP 172.16.45.1 > 172.16.45.5: GREv0, key=0x4d2, length 131: gre-proto-0x2001
…
it seems that Teltonika does not accept registration reply from hub:
image

Tunnel interfaces are pinged:
root@RUT955:~# ping 192.168.23.1
PING 192.168.23.1 (192.168.23.1): 56 data bytes
64 bytes from 192.168.23.1: seq=0 ttl=255 time=1.862 ms
64 bytes from 192.168.23.1: seq=1 ttl=255 time=1.758 ms
64 bytes from 192.168.23.1: seq=2 ttl=255 time=1.823 ms
^C
— 192.168.23.1 ping statistics —
3 packets transmitted, 3 packets received, 0% packet loss
round-trip min/avg/max = 1.758/1.814/1.862 ms
root@RUT955:~#

Is there any way I can diagnose the NHRP problem on RUT955?

3

Hello,

Apologies for the delay. Could you please confirm whether the NHRP registration issue on the RUT955 has been resolved? If not, it would be helpful if you could provide a simple topology diagram with the IP addressing scheme of your intended setup for review.

Edit:
As I understand, your issue was already registered on our HelpDesk and has since been resolved. Could you kindly confirm if that’s the case?

Best regards,

5

Hello,
Yes, that`s our case. The helpdesk helped us solve our problem!
Everything worked after enabling multicast in the NHRP settings.
Thank you!

6

Hello,

Thank you for the update and for sharing the solution here. I believe this will be helpful for other users facing identical or similar issues with DMVPN.

Kind regards,