How to find WSL2 machine's IP address from windows

This question is related to my question about making a WSL2 address static. Since that looks like it isn't possible I am trying to come up with a workaround.

I am thinking I can run a shell script in WSL2 at boot that will write the WSL2 machine's address to a file on the host system. A powershell script will look for that file, and when it finds it it will run:

netsh interface portproxy add v4tov4 listenport=4000 listenaddress=0.0.0.0 connectport=4000 connectaddress=<WSL2 IP>

If possible I'd like to eliminate the need to run a shell script in Linux.

One possibility it via netsh interface ipv4 show neighbors. 172.27.154.150 is the current ip address of my WSL2 machine, but I am not really sure how to write a script to isolate that IP address.

PS C:\Users\Nick> netsh interface ipv4 show neighbors
Interface 1: Loopback Pseudo-Interface 1
Internet Address Physical Address Type
-------------------------------------------- ----------------- -----------
224.0.0.22 Permanent
239.255.255.250 Permanent
Interface 7: Ethernet0
Internet Address Physical Address Type
-------------------------------------------- ----------------- -----------
192.168.163.2 00-50-56-fa-e9-9e Reachable
192.168.163.254 00-50-56-fc-61-94 Reachable
192.168.163.255 ff-ff-ff-ff-ff-ff Permanent
224.0.0.22 01-00-5e-00-00-16 Permanent
224.0.0.251 01-00-5e-00-00-fb Permanent
224.0.0.252 01-00-5e-00-00-fc Permanent
239.255.255.250 01-00-5e-7f-ff-fa Permanent
255.255.255.255 ff-ff-ff-ff-ff-ff Permanent
Interface 19: Bluetooth Network Connection
Internet Address Physical Address Type
-------------------------------------------- ----------------- -----------
224.0.0.22 01-00-5e-00-00-16 Permanent
Interface 14: vEthernet (Default Switch)
Internet Address Physical Address Type
-------------------------------------------- ----------------- -----------
172.21.47.255 ff-ff-ff-ff-ff-ff Permanent
224.0.0.22 01-00-5e-00-00-16 Permanent
224.0.0.251 01-00-5e-00-00-fb Permanent
239.255.255.250 01-00-5e-7f-ff-fa Permanent
255.255.255.255 ff-ff-ff-ff-ff-ff Permanent
Interface 25: vEthernet (WSL)
Internet Address Physical Address Type
-------------------------------------------- ----------------- -----------
172.27.154.150 00-15-5d-f2-6b-94 Stale
172.27.159.255 ff-ff-ff-ff-ff-ff Permanent
224.0.0.22 01-00-5e-00-00-16 Permanent
224.0.0.251 01-00-5e-00-00-fb Permanent
239.255.255.250 01-00-5e-7f-ff-fa Permanent

EDIT: See this answer for the script I wrote to automate starting SSHD in WSL and routing traffic to it

2 Answers

From Windows powershell or cmd use the command:

wsl hostname -i

This should return an IP address if WSL is running. It appears to start the default distro if not running, and then return the address of that. (takes a few seconds longer to return)

Note that while this should work for the simple case, it might not work for every distro that you might run inside WSL. In that case, you should consider Hashbrown's answer (which involves a more complicated command, but may work better)

For me my WSL has multiple interfaces so hostname isnt appropriate. In this instance you can use this:

wsl -- ip -o -4 -json addr list eth0 `
| ConvertFrom-Json `
| %{ $_.addr_info.local } `
| ?{ $_ }

Change -4 to -6 for ipv6, and eth0 to your interface of choice.