veth on MacOS

Linux virtual-Ethernet (veth) interfaces are quite useful for a variety of purposes - for me, that’s to test Ostinato.

I recently discovered MacOS also supports something similar - though they are called Fake Ethernet (feth) there.

Not much information is available on these interfaces and their capabilities, but they do seem to work like basic veth pairs on Linux.

Here’s how you can create veth-like or feth interfaces on MacOS.

Run the following commands using sudo -

ifconfig feth0 create
ifconfig feth1 create
ifconfig feth0 peer feth1
ifconfig feth0 up
ifconfig feth1 up

That’s it!

If you send traffic on feth0 you will receive it on feth1 and vice-versa.

If there’s more information about these feth interfaces, do let me know in the comments.