ethernet stops working mac pro early 2009
Mac Pro Early 2009, 10.12.6, 16 G
Both ethernet ports stop functioning as well as wifi. Sometimes Wifi connects but doesn't communicate, sometimes it just hunts without connecting to any of three available channels. I tried connecting thru an iPad hotspot. It shows connected, but no communications. Diagnostics show all green most of the time. Sometimes "Network Settings" shows red, but will eventually turn green.
Router/modem are as provided by the cable company.
Other devices use the same Wifi channels with no problem.
Rebooting the computer re-establishes communications over both ethernet and/or Wifi. I've had to reboot twice to get around this problem, but I expect it to re-occur. I'm submitting this question using the same computer after reboot.
Rebooting the router doesn't seem to make much difference.
Can the network card go stupid but fool diagnostics? Is Airport on a separate card?