Macs not connecting via Thunderbolt bridge

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Level 1

39 points

Macs not connecting via Thunderbolt bridge

I am trying to connect my 2 macs (M4 MacMini + M1MacStudio) via thunderbolt bridge. I followed the Apple Support steps on how to do this but I am not seeing any results. Both are connected to the ethernet network.

DHCP is self-assigned IP on both. I don't see the other computer using Finder. Only the ethernet hostname shows up not the TB bridge IP.

I have read the other incidences for this problem but none of them had a satisfactory resolution.

I am using a 0.5m 40GHz TB4 cable to connect between the two computers.

After setting up the TB bridges on both, how can I tell if they are configured correctly?

Is it ok to use the self-configured IP even though they are not in the same network subnet as the main network?

Mac Studio, macOS 26.4

Posted on Mar 26, 2026 6:55 PM

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Answer 1

cymorrow Author

Level 1

39 points

Mar 26, 2026 7:35 PM in response to Grant Bennet-Alder

Thanks, not sure what I did but after reverting to self-assigned IPs and rebooting, I am now able to see the other computer connected via TB bridge.

Your answer was what I was looking for as it was never clear if it is ok to use the self-IP. Thanks for that.

Now how do I name the connecxtion so it is distinct from the "normal" Ethernet based file sharing? I mean how do I tell which (*) is the TB vs Et?

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Answer 2

Mar 26, 2026 7:16 PM in response to cymorrow

self-assigned IP address are used when a device powers up. They are perfectly valid LOCAL addresses, and are all you need for computer-to-computer data transfers.

Finder > Go menu > connect to server...

... and enter the other computer's self-assigned IP address.

the credential needed are the remote computers credential for access in the files you want.

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Answer 3

Mar 27, 2026 7:14 AM in response to cymorrow

I don't think it needs a unique name.

My understanding is that when talking to other IP addresses, destinations that are not local and therefore need to be Routed are sent via the TOPMOST working interface shown in the Network pane, on their way to the Router.

Addresses that are known to be local are sent directly over the link that is "least expensive" -- typically the smallest number of hops at the highest data rates.

Ethernet takes one hop to the Switch section of the Router, plus one hop to the destination.

ThunderBolt Bridge takes one hop to the other device. Cheapest.

"It just works."

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