I am experiencing the most bizzare issue in the history of my networking and I hope you can help.
I have the UBNT Router and VyOS router.
No Firewall filters at both ends.
I can post the config of both if necessary… but hear me first
The UBNT is trying to ping the Public IP address of VyOS - Nothing.
VyOS is trying to ping the public IP address of UBNT - nothing
I go to VYOS and type:
monitor interfaces ethernet eth0 traffic filter “host PUBLIC IP of UBNT ROUTER”
Taking a bit of time… and then:
Capturing traffic on eth0 …
0.000000 126.96.36.199 -> 188.8.131.52 ICMP Echo (ping) request
0.000033 184.108.40.206 -> 220.127.116.11 ICMP Echo (ping) reply
While the capture is running like this… you go to UBNT router CLI and you can see the reply !
You stop the monitor, the PING immediately stops.
But wait it gets better.
When PING replies, the GRE tunnel between them comes up and it’s all working
Then , I go to VYOS and I stop the capture - all drops, no GRE tunnel, no PING.
I can keep the network “alive” only when I monitor ETH0 interface.
Its just CRAZY.