so this was a new one for me after 30+ years of networking
for the past 3 weeks, my mac pro decided to fall off the network randomly, every 5-45 minutes. prior to this, it had been solid for 10 years.
suspected a bad ethernet port, so i switched to the secondary port. no dice.
suspected software weirdness, so i reinstalled adguard and anything that might be hijacking my connection. no dice.
suspected a bad ethernet cable, so i swapped that out too. green lights on my pro, and on the switch. no dice.
yesterday I noticed that my doorbell cam had been mysteriously offline for some time - probably weeks. i traced it back to its ethernet cable, which was only partially inserted. the locking tab had snapped off.
oddly enough, i noticed that it neighboured the mac pro's port on the switch.
i replaced the bad doorbell cam cable. suddenly, i've got rock solid ethernet on the pro again. 😖
i assume this means there are electrical relationships between neighbouring ports on this $9 switch, probably to save money. sigh.