I know you can monitor for incoming pings on your server:
sudo tcpdump -vi enp2s0 proto \\icmp
But I just found out that it works only if the server is being pinged using its IPv4 address. When I try to ping it using its IPv6 address and ping6 command I don't seem to be getting any packets.
So the question is: how do you monitor your server when someone pings you using its IPv6 address.