Turn macOS into a Gateway with Brook

Updated at: 2024-01-01

Requirements

A macOS using wired network, since the wireless network card performance will be poor
Prevent machine from hibernating or sleeping
Although Brook supports IPV6, but many downstream devices are unable to set up IPv6 gateway and DNS, so it is necessary to disable IPv6 on downstream or upstream devices.

Run Brook

On this macOS, normally start Brook in TUN mode (which is the default), or running a tun2brook is also fine.

Note that you should disable FakeDNS(The GUI defaults to having FakeDNS enabled). Because other devices do not have the route to the Fake IP, they can't communicate back, of course, you can tweak things yourself, but the I think this is a bit cumbersome and unnecessary.

Enabling Forwarding

sudo sysctl -w net.inet.ip.forwarding=1

Test

Try on other device:

Then set the gateway of the other devices to the IP of this macOS
Then set the DNS of the other devices to 8.8.8.8
```
curl http3.ooo -v
```

Traffic Splitting

Try bypassing the IP of http3.ooo with Brook or tun2brook on the macOS gateway device 137.184.237.95/32.

Try on other device again:

curl http3.ooo -v

Discuss