It looks like the router is blocking snmp through the wireguard tunnel

I have setup my router to reach out and connect to a cloud server with wireguard. So far it seems to be working. I can ssh through the tunnel, access https sites through the tunnel, and even query the PiHole container providing DNS through the tunnel. However, I cannot query snmp through the tunnel.

I have setup the cloud server to open port 161 and 53 on the wireguard interface

sudo ufw statusStatus: active
To                         Action      From
OpenSSH                    ALLOW       Anywhere
Nginx Full                 ALLOW       Anywhere
60031                      ALLOW       Anywhere
53/udp on wg0              ALLOW       Anywhere
161/udp on wg0             ALLOW       Anywhere

When I run tcpdump -i wg0 -n udp I can see attempts to connect to port 22 and 53 just fine with nc but when I nc -v SERVER_IP 161 the attempt times out and the tcpdump shows nothing.

I am thinking something on my GL-MT6000 is blocking the traffic. But I am not sure what could be doing it. I had to adjust the firewall in LuCI to allow traffic from wgclient1 and lan, but beyond that I didn’t have to do anything to allow 22, 161, 80, and 443 traffic through the tunnel. I shouldn’t have anything that would be blocking 161 in the firewall rules, but that is the only thing I can think of that could be causing this problem.

Sorry, I was testing with sudo tcpdump -i wg0 -nn udp on the server and from the other side of the Wireguard tunnel, nc -u -v 10.8.0.1 53 which shows in the tcpdump and nc -u -v 10.8.0.1 161 which doesn’t.

Hi

Can you draw a simple network topology so that we can better understand this issue?
Please be sure to label IP addresses, WireGuard VPN addresses, and device roles (WireGuard server/client, SNMP Management/Agent).