Craig HockenberryI found a network problem that wasn't DNS.
It was Energy Saver.
sidb has moved to mstdn.social@chockenberry It’s probably because Energy Saver hits the DNS wrong :)
@sidb As soon as I wrote that I thought the same thing 😀
Eric Vitiello@chockenberry wow I never would have thought of that one. Nice detective work!
Dave Anderson@chockenberry the paragraph that starts with "When I turned the Energy Saver" has a lot of ons and offs that get confusing without tagging each with context. Possibly edit post if you still can, thx for the heads up tho
@mrdaveanderson Yeah I noticed that after I posted. Can’t edit. At least screenshots are clearly labeled.
manolo@chockenberry wow, nice find that’s wild
sam
Brendan Shanks@chockenberry Geez, so basically when that Mac goes to sleep it breaks everything. I have old Macs (2013 Pro, 2018 mini) that are mostly sleeping until I remote into them, haven’t seen that issue. But on Ubiquiti switches, not a UDM.
I do notice that when they’re sleeping, those Macs drop back to “Fast Ethernet”/100 rather than GigE when they’re on.
Zimmie@chockenberry Do you happen to have a spare switch which can run port mirroring? It’s likely this problem is caused by a single packet hitting a parser in the UDM which can’t handle it. A packet capture would make that a lot easier to reproduce, and a switch with port mirroring would allow you to run the capture outside the endpoints at issue.
I’m not with Ubiquiti at all, I’ve just done more network kernel work than the average bear.
Stefan 
Jan Lehnardt 
@chockenberry thank you for documenting this 🙏
Mike Piontek@chockenberry Interesting. I’ve been struggling with an issue that’s a bit different but has a lot of things in common. In my case I’m just getting brief outages, usually around 30 seconds. But one thing I’ve noticed is that if someone wakes up our Mac Studio, the UDM loses its internet connection nearly every time.