Why does Mac OS X and Linux do not ping each other on a local Ethernet Network?

With a simple Netgear four ports switch-hub, when connecting via RJ45 cables osx boxes and Linux boxes and seting static ip addresses, one is able to arping but not ping to/fro different operational systems. Why is that, please?

I can see routes to the Linux boxes on osx netstat -r. But pings from osx to linux timesout. Same goes for linux pinging OSX. Arp tables are correct and were updated automatically not manually.

Ten years ago someone asked the same and did not get an answer: Which setting in osx could block "ping localhost"?

In my case, no, OS X firewall is NOT in stealth mode and it’s not even running. I have turned it off to do the experiment.

This has been posted on Mac Support website: https://discussions.apple.com/thread/253430208