Mac mini M1 ethernet doesn't work after waking from sleep

Ok so I'm back and on osx mac mini 11.6 16g ram, and I just experienced a "drop*", I might have found a way to fix the connection after the drop (without rebooting, unplugging any cables etc), but this is not a preventative to the drop itself.. but I wanted to share how I did this in case it helps someone

(What do I mean by my drop* event)

• This dropped happened to me while I was viewing my m1 mac through a splashtop session / (similar to rdp/vnc), just an immediate connection cut off
• Outbound pings to google.com fail
• I also notice outbound UDP also stops (I've been spamming a remote cloud server for testing, confirmed it stops)
• any kind of tcp outbound requiring dns resolution just fails (like navigating to google with safari etc)
• interface en0 is still online, wifi is still online
• I run splashtop streamer on this and my m1 host shows offline

(So heres whats strange, and what I did)

• file sharing appears to still be working, I assume this is because of established connections between my mbp and mac mini, or bonjour broadcast etc (though it was very likely it would eventually fail soon, I browsed some folders to make sure it wasn't just some cached finder session)
• well what if the interface rebooted and came back online ?
• to test that, I sshed into the mac mini from my mbp and it SUCCEEDS.. odd I thought the interface dropped and was unresponsive ?
• OK, did my m1 run out of file descriptors ? ( well sudo lsof | wc -l never completes, I didnt want to wait longer than 3 minutes so I cannot confirm this, but I can assume something possibly may have hung/defunct/zombie fd)
• checked dmesg, looked fine..
• /var/log/system.logs, nothing really odd off the bat
• still confused, so I then ran a ping test outbound to google.com (this works on my other machines but not the m1)
• 
• checked en0 for status:
• 
• OK now I suspect either nslookup/dhcp problems, so I'll try to resolve these one at a time starting with DHCP first:
• DHCP manually reassign command = ipconfig set en0 DHCP
• 
• oh.. that fixed it

I still don't have enough information but.. If anyone gets another drop* one day and you have physical/or/ssh access to your m1 machine try to fix dhcp with "sudo ipconfig set en0 DHCP" and see if your connection comes back and maybe post here too if that worked for you (also replace en0 with your interface id, check that with "ifconfig", you should see your ipv4 somewhere in there and most likely it is that interface)

I still have no idea how the interface "dropped*".. but I hope this info helps someone out there

Has anyone tried setting advanced nic settings to

full-duplex, flow-control ?

Mine defaults to

full-duplex, flow-control, energy efficient ethernet < and I think this is why my nic keeps dropping after a period of inactivity

I'll try it for a week and see how it goes

heres how you do that:

then hit ok > apply

Well, that’s new material information which you didn’t disclose prior i.e. you’re hard-coding connections which makes your configuration special. Sorry, no attaboy forthcoming. Unfortunately, it also means your binds are a credible root cause of your network wake issue = good luck looking for a solution, you’ll need it. Bye bye.

Moshe Gottlieb wrote:

Thanks @den.thed, ethernet is already on top, otherwise I wouldn't have noticed the issue.

I need the wifi connection as well (for air drop, side car) so turning it off is not an option, nor will help:

The ethernet connection appears to be working, and since it's first, macOS tries to route everything through it anyway (and fails).

Those services should also work thru your local network with the Mac connected to Ethernet and the other devices connected to Wi-Fi.

Your problem now, is that the iMac is confused when it first wakes up.

Same problem with mine. I use a static address. The routes seem to get confused. Tried shuffling the ethernet settings around, to no avail. Instead of restarting, doing "ifconfig en0 down" followed by "ifconfig en0 up" fixes it for me. Still annoying, as my remote ssh and X sessions all get nuked by this.

Actually I think this has happened to me without the machine going to sleep as well. In the middle of doing something and noticing that I can no longer save to a network share because ethernet has gone awol. Anyway it doesn’t always happen to me when the machine sleeps. I’ve yet to figure out how to cause this anomaly and my TCP dumps on box connected to same switch also show nothing to indicate a cause.

I have this issue constantly with a mac mini m1 plugged into a gb switch. Regardless of cable or port, the mac mini will simply not work with the nic if this state triggers. Specifying a manual IP doesn't matter. The OS seems to have a bug relating to self-assigned IPs and switching the config of the nic.

I always end up enabling wifi to get around the internal network stack bug. It's been repeating constantly since I bought this mac mini last month.

just bought a new mac mini m1 today

and i encounter exactly the same issue

my Ethernet loss connection randomly, replugging doesn’t help, only reboot can fix the bug temporarily, after a couple minutes, it will loss connection again.

Well one thing for sure, hcsital didn't add much to the conversation, sorry you had to deal with that Moshe.

I got an m1 mac mini and same thing, wifi works - ethernet didn't.

I was able to get ethernet working (able to go online) by not only assigning manual ip settings but also had to manually assign the DNS servers in advanced settings. (Bottom right)

(If you don't know your DNS servers you can locate your them by logging into your modem and seeing what the 2 [usually 2] DNS servers are)

After that it worked well, until sleep like some of y'all said. It then seemed to fail, but it was actually just incredibly slow! I was still getting network capability but it was spotty and about 300 BITS/SEC (not mb or kb straight up bits!) when it did work.

Just updated to Big Sur 11.2.2 and will test to see if that fixes it. Otherwise I'm going to also try a usb-c -> ethernet adapter I have. I am running this little guy as a server for multiple operations so wifi-only isn't really an option.

Sorry for the Johnny Come Lately post. I am having similar issues but not after sleep.... at least not yet. However I do lose DHCP and even though I have the WiFi enabled and on it will not switch to the WiFi as my MBP that I had in its place would do. The NIC still thinks it has a valid route via the Interface that is APIPA addressed. What worked for me as a band-aid is to turn off the interface and turn it back on.

I opened a case with Support but as usual, they do not have a fix. Its always a "re-install" blah blah. I wanted to increase the verbosity of the logging to see if I or "support" could identify a root cause before I experience the issue. They are not aware and say that they need to send it to "engineering", which is a blackhole of regret with them.

I may attach a USBC Ethernet dongle to see if the same thing happens. It is not my switch since I had my MBP plugged in for 1.5 years without any issues, it is not my "router" (as support loves to say) I work for the mfg of the firewall (router) and can guarantee that is not the issue. Not the cable either because of the aforementioned.

Let us know here if you come up with something. I will do the same. I created another post because I had not see yours. Will, update both.