Mac Studio, internet connection keeps disconnecting periodically

10Gb Ethernet:

"energy efficient" drops power to the 10Gb Ethernet chip to save energy. It is NOT compatible with Top Speed. In the hardware pane, under Duplex, set: “Full-Duplex, Flow Control” NOT “Full-Duplex, Flow Control, power efficient” to disable power saving and boost top speed.

The Mac Studio has a 10Gb Ethernet port. If you have some fancy equipment at the other end of the cable, it is possible it is trying to make a 10Gb connection.

A 10Gb (or 5Gb or 2.5Gb) connection is only stable when cables are excellent and fairly short (like Category-6 rated cables under 100 feet). If either of those are not true, or you have you added patch cables that are not Category-6 rated, you could be seeing it connect at a faster-than-Gigabit speed, then error out and disconnect.

Actual Speed:

The good way to check the actual connection speed USED to be Network Utility, But in Big Sur and later, Apple has deprecated network Utility and now you have to use a Terminal command to see your actual connection speed. First, you need to know what en number the link is. then you use a command like this one, substituting the actual en number.

my main Ethernet connection uses BSD name en5 (as shown in) :

 menu > about this Mac > (system report) > network:

ifconfig en5 | grep media

with this as my output:

media: autoselect (10Gbase-T <full-duplex,flow-control>)

For Gigabit Ethernet, you should get this instead:

media: 1000baseT <full-duplex,flow-control>

Errors detected:

To see if an Ethernet link is throwing more than a handful of initial errors, you can use Terminal command:

netstat -I en5

This is the resulting output. Counters are In-packets, In-errors, Out-packets, Out-Errors, Collisions. There should never be more than handful of errors from starting up, and in most cases, NONE.

Name       Mtu   Network       Address            Ipkts Ierrs    Opkts Oerrs  Coll

en5   8163  <Link#4>    00:01:d2:1a:00:dd   696697     0   484301     0     0

en5   8163  grantsmacpr fe80:4::461:ea0d:   696697     -   484301     -     -

en5   8163  192.168.0/23  192.168.0.204     696697     -   484301     -     -

If the link were running beyond its ability to run and be stable, for example it auto-speeded to 10Gb but the cabling could only reliably support 2.5Gb, we would see non-zero errors counts, and errors increasing over time. (and possibly, disconnecting)

do you remember what you have changed so far?

There is one more thing to check. Packets going to the Internet will be sent through the TOPMOST, working interface show in the list at system preferences > Network.

If Ethernet is not TopMost, use the gear icon under the box, choose "Set Service Order" and drag Ethernet topmost.

most of my large response above presumes one of two issues:

Ethernet Power saving. (have you turned that feature OFF?)

You do not appear to be having speed-mismatch or other issues related to errors on the link (that's good!)

if you are using a VPN provided by your Institution or employer, that is great. they can help you with that.

if you are using a VPN you installed thinking it would improve PROTECTION -- it does nothing of the sort. It is just Scare-ware. It has no place on your already well protected Mac, and could be the source of slowness, disconnections, and crashes.almost every web site you visit uses httpS: encryption. if traffic monitoring were possible, it would yield gibberish.

As long as your computer is behind a Router YOU control, your computer is protected and unreachable from the Internet. The Router translates your local private Address in to its address, and acts as your agent on the internet. Any request that shows up unsolicited is discarded by default. There is no need to have the computer firewall turned on, and that can also lead to slowness.

If you leave Wi-Fi off, it can make location determination more difficult and less precise. Your Router knows where it is in the world, and can tell your computer when asked over Wi-Fi.

'full duplex, flow control' is slightly better if you have that choice under

Duplex:

No outbound packets still says Not working.

Those addresses are in the strictly-local IP address ranges. Half the computers in the world are using a strictly local IP address in the range 192.168.xxx.yyy and most of the rest are using 10.xxx.yyy.zzz and a few more are using 172.16-31.xxx.yyy

https://en.wikipedia.org/wiki/Private_network

... they are not routable outbound, and not reachable inbound to/from the Internet at large.

if that is the correct en_ number, that connection is not working. It has no IPv6 or IPv4 address, and it has sent NO packets out.

ALL that stuff is just scare-ware. Your Mac is already really well protected. Nothing can become executable unless it is Developer-Signed and you approve it with your Admin password. The System Volume is in accessible for writing, locked and checksummed. In the extremely unlikely event something manages to modify anything on the system, you get an error message.

Effective defenses against malware and ot… - Apple Community

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