WSL2 SSH RemoteForward connect back

Question

I'm trying to use rsync on my dev server to download files to my local machine after checking out a branch on the dev server.

Before using wsl2, I used to be able to do the following:

Remote server

rsync -ave "ssh -p 22001" --delete --exclude-from ~/rsync_exclude_list.txt ~/as/ alex@localhost:/home/alexmk92/code/project

Local SSH config

Host dev-tunnel
    HostName dev.sever.co.uk
    User as
    ControlMaster auto
    ControlPath ~/.ssh/sockets/%r@%h:%p
    RemoteForward 22001 localhost:22

Host dev
    HostName dev.server.co.uk
    User as
    RequestTTY yes
    RemoteCommand cd as; bash

I can then run these with ssh dev and ssh -fvN dev-tunnel if from the remote server I type ssh -p 22001 alex@localhost then I get:

debug1: remote forward success for: listen 22001, connect localhost:22
debug1: All remote forwarding requests processed
debug1: client_input_channel_open: ctype forwarded-tcpip rchan 2 win 2097152 max 32768
debug1: client_request_forwarded_tcpip: listen localhost port 22001, originator 127.0.0.1 port 34472
debug1: connect_next: host localhost ([127.0.0.1]:22) in progress, fd=5
debug1: channel 1: new [127.0.0.1]
debug1: confirm forwarded-tcpip
debug1: channel 1: connection failed: Connection refused
connect_to localhost port 22: failed.
debug1: channel 1: free: 127.0.0.1, nchannels 2

I'm guessing this is because WSL2 no longer runs on localhost, and is instead isolated within Hypervisor. Which probably means windows is receiving this request on localhost:22 (where no SSH server is running) and then hangs up the connection.

How can I forward the request to my WSL2 SSH process?

Answer 1

It is possible to add a port mapping to WSL2 machines, using the following WSH script:

$port = 3000;
$addr = '0.0.0.0';
$remoteaddr = bash.exe -c "ifconfig eth0 | grep 'inet '"
$found = $remoteaddr -match '\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}';

if( $found ) {
  $remoteaddr = $matches[0];
} else {
  echo "Error: ip address of WSL 2 cannot be found";
  exit;
}
Invoke-Expression "netsh interface portproxy delete v4tov4 listenport=$port listenaddress=$addr"
Invoke-Expression "netsh interface portproxy add v4tov4 listenport=$port listenaddress=$addr connectport=$port connectaddress=$remoteaddr"

echo "Success: Port mapping added!";

Of course, you need to change to port and maybe the IP address (first two lines) Maybe you need to run the script as admin...