Mesa ethernet vs internet connection

Have you used the /etc/network/interfaces method of configuring the wired interface? This is described in the manual page, "man 9 hm2_eth" at the terminal or linuxcnc.org/docs/html/man/man9/hm2_eth.9.html online.

I believe that if you are relying on the automatic configuration known as NetworkManager, it will automatically disable a NetworkManager-controlled wired interface when activating a NetworkManager-controlled wireless interface.

Note that if your system has 1 wired and 1 wireless interface, the name of the wired interface may be "eth0" instead of "eth1" as shown in the example. The terminal command "ifconfig -a" will list the names of all installed network interfaces.

The /etc/network/interfaces file has to be edited as root, and the easiest (but not quickest) way to apply changes is to reboot after editing the file.

It may be possible to do something in NetworkManager with the graphical tools to allow both a wired and wireless interface to be active at the same time, but I am not familiar with how to do it. I hope someone more accustomed to using the GUI tools will chime in if this is possible.

It occurs to me that you can divide the problem into either local configuration OR hitting a corner case that hm2_eth doesn't handle:

In the terminal, "ping" the board. If you have a situation where the pings work, but hm2_eth doesn't start, then it's more likely that we should look at this as a hm2_eth bug.

If the ping doesn't work either, then it's more likely that we should look at this as a network configuration bug, and improve the documentation once we have a handle on what the fix is.