You’ll forever be spidered online, don’t think twice about this one.
Russia/china/you name it servers will send out exploitive calls to your forwarding IP to find leaks in your network. Remember we’re just on a simple IP system 188.8.131.52; it’s very fast to rip through the list and hit public facing servers at their port/etc.
So accept this traffic just ensure you’re secure/safe and maybe not allowing ICMP or other ports to be exploited in these regards. Bouncing pings off server is common DDOS tactics, regardless of a blocked port though if online all and any client/server can test you so just allow it and be BETTER…
I get word-press exploits daily on my IP every 10 -90 minutes, soft-core wanna be hacky stuff but doesn’t work if you good with what you do.