macOS Random Networking (Ethernet) Failures

[fishcharlie]

About once per day (sometimes more or less) and usally overnight, the networking will fail on my Mac mini running 11.2.1. When this occurs all pings in the Terminal fail (to both local and remote IP addresses). So even trying to ping my router fails. Which is strange because in System Preferences it says Ethernet is connected, and it's hard wired into my router. So it really shouldn't be failing.

When this occurs I tried to go into System Preferences and renew my DHCP lease. But that results in it receiving a self assigned IP. Which is weird because my router has this device set to have a static IP (10.0.0.2).

The only way to fix this is to restart the computer. Unplugging and replugging in the Ethernet doesn't work, and restarting the router doesn't work.

At first I thought this could be a DHCP issue or something. So I decided to try to set the IPv4 mode to Manual in System Preferences instead of DHCP, and entered that static IP (10.0.0.1) along with my router IP and subnet mask. This worked for 2 days (instead of 1) then failed again. Not sure if the fact that it worked longer was a random anomaly or if it did make some type of difference.

I had the idea of writing a script to ping my router every 30 seconds and if it fails to restart the computer. This caused the network to fail a LOT more frequently (like after a few minutes), and the restart I couldn't get working due to permissions, but due to the fact that it was failing a lot more frequently, I gave up on this idea.

Has anyone else experienced this in Big Sur? Does anyone have any workarounds to get Networking to be more stable?

 

[appltech]

If you cannot ping even your router, there's a bad connection between your computer and the router. So:
1. Try another port in router.
2. Try another cable.
3. Why would you use 10.x.x.x IP anyway? 192.168.x.x range is more than enough for home. And, usually, you cannot assign the number 1 IP from a range (e.g. 10.0.0.1 or 192.168.0.1), since it's reserved for the router itself, but that depends.
Still, I'd say it's a faulty cable or port.

 

[BrianBaughn]

Have you tested you current configuration with absolutely nothing else connected to the router by ethernet or wifi? By nothing else I include access points and switches.

 

[fishcharlie]

@appltech

1. Tried another port already
2. Tried another cable as well. If either 1 or 2 is accurate, then why would it also work part of the time? That doesn't quite add up to me.
3. Because I'm more used to it and it's less to type when trying to SSH into the device. No clear benefit to me to using 192.168.x.x. 10.x.x.x works fine. I'm aware about the 10.0.0.1, that is why this device is 10.0.0.2.

@BrianBaughn I have not. I'm not sure I'm able to do that. It takes about a day or sometimes two to have the problem occur. So unless it's a last resort debugging tip, I'd prefer to not go a day+ without internet.

 

[appltech]

What about router's firmware? Check if there are any updates (on the router's manufacturer website, I suppose).