Problem solved! Help configuring Thunderbolt sharing for Internet between two M1 Macs

[BeatCrazy]

UPDATE: Problem solved!

Ended up calling Apple for help. After the normal troubleshooting, I had the idea to unplug the ethernet connection from the client machine/iMac. That worked!

Somehow, when you have Ethernet connected, it overrides internet from the Thunderbolt bridge. Who knew ha.

In case anyone is curious, passing internet via the Thunderbolt bridge seems to lose about 15% throughput. I have 5Gbps fiber service from AT&T. My host/Mac Studio typically gets 4,700Mbps up/down. Via the Thunderbolt bridge, the iMac tests at ~ 4,100Mbps up/down. Definitely better than the 1Gbps built in connection.

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original post:

I have a Mac Studio, and 5Gbps internet service. I'd like to share this via Thunderbolt to my M1 iMac.

I have configured the Mac Studio to share internet via Ethernet via Thunderbolt Bridge:

However, the receiving iMac doesn't recognize, only showing Thunderbolt Bridge in 'Unknown State'. I've tried different cables, this is a config/software issue.

 

[ssmed]

I suspect you need to use manual addressing on both machines for this connection within the subnet and IP range of that provided by your ISP router using DCHP. Also make sure the DNS servers have valid entries. If you need to put something in then 8.8.8.8 (google DNS would be OK)

What does it say under TCP and DNS on the screen above.

 

[BeatCrazy]

I suspect you need to use manual addressing on both machines for this connection within the subnet and IP range of that provided by your ISP router using DCHP. Also make sure the DNS servers have valid entries. If you need to put something in then 8.8.8.8 (google DNS would be OK)

What does it say under TCP and DNS on the screen above.

Thanks. I was expecting the DHCP to happen automatically. Please see below:

 

[ssmed]

That looks OK - what is the other end saying - it is similarly filled in?

 

[BeatCrazy]

That looks OK - what is the other end saying - it is similarly filled in?

The host machine looks like this, Thunderbolt port 3 is connected to the destination iMac.

 

[HDFan]

I run a thunderbolt connection to my NAS which give it internet access. Home ethernet network is 10.0.0.0 mask 255.255.255.0 router 10.0.0.1. Internet sharing is off.

On my Mac Side I have:



On the NAS side


Maybe this will help.

 

[BeatCrazy]

I run a thunderbolt connection to my NAS which give it internet access. Home ethernet network is 10.0.0.0 mask 255.255.255.0 router 10.0.0.1. Internet sharing is off.

If Internet sharing is Off on your Mac, how is the NAS getting internet?

 

[ssmed]

I think you need to break this down.

1. can the Macs see each other on file sharing with other networking options turned off (regardless of access to the internet
   Try Mac 1 192.168.2.10 255.255.255.0 and Mac 2 192.168.2.11 255.255.255.0
2. Then look at internet sharing (it is a long time since I did this and never on Ventura) ensure that the DNS is correct on both machines and the internet sharing is on appropriately.

 

[Cabin]

Try this:

ping 192.168.2.10
ping 192.168.2.11

Let us know what the result is?

 

[HDFan]

If Internet sharing is Off on your Mac, how is the NAS getting internet?

Have no idea. Maybe not required as it is a NAS-Mac rather than a Mac-Mac connection.

 

[BeatCrazy]

I think you need to break this down.

1. can the Macs see each other on file sharing with other networking options turned off (regardless of access to the internet
   Try Mac 1 192.168.2.10 255.255.255.0 and Mac 2 192.168.2.11 255.255.255.0
2. Then look at internet sharing (it is a long time since I did this and never on Ventura) ensure that the DNS is correct on both machines and the internet sharing is on appropriately.

Yes, the Macs can see each other when both ethernet and Wi-Fi are disabled. I can use screen sharing to control/access the other one.

Try this:

ping 192.168.2.10
ping 192.168.2.11

Let us know what the result is?

Please see below:

 

[BeatCrazy]

UPDATE: Problem solved!

Ended up calling Apple for help. After the normal troubleshooting, I had the idea to unplug the ethernet connection from the client machine/iMac. That worked!

Somehow, when you have Ethernet connected, it overrides internet from the Thunderbolt bridge. Who knew ha.

In case anyone is curious, passing internet via the Thunderbolt bridge seems to lose about 15% throughput. I have 5Gbps fiber service from AT&T. My host/Mac Studio typically gets 4,700Mbps up/down. Via the Thunderbolt bridge, the iMac tests at ~ 4,100Mbps up/down. Definitely better than the 1Gbps built in connection.

 

[BsdGuru]

This is old, but the problem was solved purely but luck; sort of like hitting the radio with a hammer and it works!

First, internet sharing is to allow other machines to share your internet connection. Like you could set the mac up as a wireless access point. Its not needed to connect machines via ethernet directly.

Second, the mac gui sucks rocks when it comes to using thunderbolt as ethernet. The default "Thunderbolt Bridge" is very confusing. Bridges aggregate 2 interfaces, such as tying together the ethernet and thunderbolt as a tunnel. In this case, you don't need or want a bridge.

Consider your thunderbolt as if it's just another ethernet inerface and configure it the same way. To completely geek out for you unix folk, Thunderbolt 1 is just en2. Without the Gui from a terminal:

ifconfig en2 17.1.1.1/24  (on system 1)
ifconfig en2 17.1.1.2/24 (on system 2)

And bang you're up and running.

PING 17.1.1.2 (17.1.1.2): 56 data bytes


64 bytes from 17.1.1.2: icmp_seq=0 ttl=64 time=0.377 ms

if you do it manually that way Im not sure it will be set up when you reboot.

Via System Settings -> Network, just create a service for Thunderbolt 1 and configure it as a standalone ethernet interface.

No "Virtual Interface', router or DNS required.

Mpte tjat upi meed tp delete the thunderbolt bridges before doing this. The MAC GUI isn't good at detecting if a device is being used on a brodge, which is probalby how the OP got his to work by removing the ethernet cable.

It's astonishing that after 12 years there's really no instruction from Apple on how to do simple, very powerful things. This is much faster than ethernet, and if you're mouse sharing or dragging folders it's really the way to connect 2 machines.

 

[wills11]

This is old, but the problem was solved purely but luck; sort of like hitting the radio with a hammer and it works!

First, internet sharing is to allow other machines to share your internet connection. Like you could set the mac up as a wireless access point. Its not needed to connect machines via ethernet directly.

Second, the mac gui sucks rocks when it comes to using thunderbolt as ethernet. The default "Thunderbolt Bridge" is very confusing. Bridges aggregate 2 interfaces, such as tying together the ethernet and thunderbolt as a tunnel. In this case, you don't need or want a bridge.

Consider your thunderbolt as if it's just another ethernet inerface and configure it the same way. To completely geek out for you unix folk, Thunderbolt 1 is just en2. Without the Gui from a terminal:

ifconfig en2 17.1.1.1/24  (on system 1)
ifconfig en2 17.1.1.2/24 (on system 2)

And bang you're up and running.

PING 17.1.1.2 (17.1.1.2): 56 data bytes


64 bytes from 17.1.1.2: icmp_seq=0 ttl=64 time=0.377 ms

if you do it manually that way Im not sure it will be set up when you reboot.

Via System Settings -> Network, just create a service for Thunderbolt 1 and configure it as a standalone ethernet interface.

View attachment 2324723

No "Virtual Interface', router or DNS required.

Mpte tjat upi meed tp delete the thunderbolt bridges before doing this. The MAC GUI isn't good at detecting if a device is being used on a brodge, which is probalby how the OP got his to work by removing the ethernet cable.

It's astonishing that after 12 years there's really no instruction from Apple on how to do simple, very powerful things. This is much faster than ethernet, and if you're mouse sharing or dragging folders it's really the way to connect 2 machines.

This sounded like an elegant solution and I tried it, but the Terminal command didn't work—not sure why, but after rebooting, I was unable to successfully ping.

As you can see from the screenshots, en2 appears to be "active" on one device, inactive on the other. Just FYI, the Mac on which it's "active" is an MBR with no ethernet port or adapter, and the one on which it's "inactive" is a Mac Studio with ethernet. I tried to delete the en2 interfaces, using two methods I found online, but neither worked:

"ifconfig en2 delete 17.1.1.1" returned error "ifconfig: ioctl (SIOCDIFADDR): Can't assign requested address

"ifconfig en2 0.0.0.0" returned error "ifconfig: ioctl (SIOCAIFADDR): Invalid argument"

Lastly, I'm unable to create a new "Thunderbolt 1" (or 2, 3) interface—I select it, but no new interface shows up in the list. I am able to create a new Thunderbolt Bridge, however.

Would so appreciate any help—thanks!

William

 

[Adora]

This sounded like an elegant solution and I tried it, but the Terminal command didn't work—not sure why, but after rebooting, I was unable to successfully ping.

As you can see from the screenshots, en2 appears to be "active" on one device, inactive on the other. Just FYI, the Mac on which it's "active" is an MBR with no ethernet port or adapter, and the one on which it's "inactive" is a Mac Studio with ethernet. I tried to delete the en2 interfaces, using two methods I found online, but neither worked:

"ifconfig en2 delete 17.1.1.1" returned error "ifconfig: ioctl (SIOCDIFADDR): Can't assign requested address

"ifconfig en2 0.0.0.0" returned error "ifconfig: ioctl (SIOCAIFADDR): Invalid argument"

Lastly, I'm unable to create a new "Thunderbolt 1" (or 2, 3) interface—I select it, but no new interface shows up in the list. I am able to create a new Thunderbolt Bridge, however.

Would so appreciate any help—thanks!

William

Hi, I just found your thread a few hours ago. I wanted to use Thunderbolt to copy files over from one Mac to another and always got Ethernet speed only. I also have some of the problems you mentioned here, like creating a service doesn't work.

You need to put sudo in front of the ifconfig commands. I also tried all this and got a connection, that is only visible in Terminal, although ping gives only errors too and Ethernet still is used instead if not disconnected.

For doing this in Network settings permanently I had the option only on one Mac without using Brigde to create a new service. I did not try if that maybe worked together. But when choosing TB1 or 2 like in the picture here just nothing happened.

This is my thread:

https://forums.macrumors.com/threads/how-do-i-make-my-macs-use-thunderbolt-bridge-instead-of-ethernet-or-wifi-for-file-sharing.2453153/

Edit: I forgot to mention @BeatCrazy I thought you opened the thread, sorry. Confused as always... 🙈