Mac Studios with faulty ethernet ports? Internet connection disconnecting periodically

10GB Ethernet:

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)

my update

So I’ve still been having this bad Ethernet port issue, now 1 month later. Speeds vary from 100% to 10% of the speed of my other computers on the same network. It usually runs at 10%. I won’t use Wi-Fi Because of security issues. 

The only fix that works is plugging the Cat6 cable into the thunderbolt port with an adapter. But i shouldn’t have to do that with a new computer. 

I took it to apple store 2 days ago. They were able to duplicate the issue using my system log in. So they did an overnight port test and is passed. Then they did a clean OS install and it passed again. 

I brought it home and restored my Time Machine backup and the problems returned. So it’s a software issue. I’m not running anything port heavy. Just Adobe suite and Protools. 

So I guess I just have to wait for a software update to Monterey or my 3rd party

programs. 

The joys of 1.0 computers. 

so the solution for you was:

set Full Duplex, flow control

disable energy-efficient

increase the MTU off the default 1500 to something more like 8000

try disabling power-saving Ethernet features and disabling Limit IP addresss tracking, two new features that may be causing some of these issues.

I'm having weirdness where I'm not able to connect to some of my internal web servers through http after it wakes up from sleep. Flipping the MTU from Jumbo to Standard and then back to Jumbo frames fixes it every time though.

Not sure if it's related at all to your issue though since I can replicate it on command rather than the issue happening randomly.

What is your MTU set to?

'energy efficient' is a feature added because of extra power required for speeds OVER a gigabit. These sometimes take extra power to get through, especially if your cables are long or less than perfect, so Apple is giving you the option to tone it down when not actively transferring data.

This should not be needed for Gigabit and slower, so no penalty for turning the feature off.

I just connected my Studio Max to ethernet and turned off wifi and no problem with using ethernet with "Configure automatically" hardware setting.

The ethernet connects to gigabit switch via cat5 cable. The switch connects to an AmpliFi Alien mesh router via cat5 cable.

Thanks. Will do. Had no trouble when copying from Mac-to-Mac by ethernet bypassing the router. So, maybe there's an issue between macOS and some routers.

It's been a bit weird as Migration Assistant copied files across my network for 9 hours without a trouble. But Finder seems not so reliable.

I’m having a similar issue with my Ethernet connection with my brand new Mac Studio Ultra. 😢 I’m close to returning it, but before I do, I’m having AT&T to send a new router and using the suggested changers above. No success as of now with the old router, even with the new setting changes listed above.

Any suggestions???

Yeah, I’ve got the Ethernet port dropping out too. Especially after wake from sleep.

Sometimes several restarts are required before it fixes itself. Cord to the router is 20 feet.

I tried all tips here but I can’t find the disable energy-efficient button. Where is that? 

I hope this is a 1.0 version software problem. 

Could this cause Finder crashes ? I have had 3-4 major Finder crashes while copying a large number of files across my home network. I'm using a Studio Max with macOS 12.3.1.

It would be worth trying the work-around suggested directly above.

Readers feel for you situation, but you have failed to include your SYMPTOMS.