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Alex Antsiferov
Alex Antsiferov

Posted on • Edited on

Troubleshooting WSL + localhost:3000 'connection refused' issue

Just spent an hour trying to figure out why the browser wouldn't open localhost:3000 (served by Webpack/create-react-app in WSL2).

Normally, a server running in WSL should be accessible from the Windows (host) machine without any issues.

My troubleshooting steps, roughly:

  • check /windows/system32/drivers/etc/hosts file --nothing special here...
  • check Windows firewall rules, just in case
  • shut down WSL VM with wsl --shutdown command and restart it
  • run another app in WSL using a different port -- hmm, this works...
  • change the port of the app in question in Webpack config: PORT=3006 react-scripts start -- also works... so the problem is in the specific port!
  • see if some process is holding the port 3000 in Linux: ss -tulpn
  • check if a process is holding the port in Windows: netstat -ano | findstr :3000 or Resource Monitor -> Network tab -> Listening ports -- aha! there is one!
  • find the process name by PID in the Task Manager -> Services

Turns out, the port was taken by IP Helper service (iphlpsvc).

I could not find a way to reconfigure it, and some quick research showed that it wasn't a critical service (at least in my case), so I just disabled it in the Services.

Top comments (9)

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royalrex profile image
Sebbe Selvig

I found that changing the port helps, each time I shutdown my webpack-dev-server and my laptop, the next day the port is "dead" again.

Using wsl --shutdown works, so starting my day with that command solved any issues, quite annoying.

The port issue is not a problem for other appliances as docker containers.

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ciprian_42 profile image
Ciprian

I signed up to dev.to only to like this comment :)

I was tired of restarting my PC to get Nuxtjs working and couldn't find any other fix to this bug.

You Sir have saved my life, haha.

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acornwall profile image
Alexandria Cornwall

Just a quick heads-up: Disabling iphlpsvc can break TCP forwarding from WSL 2. You might use this feature, for example, if you're trying to debug locally from your phone: github.com/microsoft/WSL/issues/4150

I don't really have a solution other than disabling iphlpsvc, starting up node / yarn, then re-enabling iphlpsvc (or just choosing a different port to start on).

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maxim_mazurok profile image
Maxim Mazurok

This command causes the port to get hogged by IP Helper:

iex "netsh interface portproxy add v4tov4 listenport=$port listenaddress=$addr connectport=$port connectaddress=$remoteport";
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And this command can un-hog it:

$addr='0.0.0.0';
$port=3000;
iex "netsh interface portproxy delete v4tov4 listenport=$port listenaddress=$addr";
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But you do loose port forwarding from WSL to Windows in this case.

Also, in my case I was able to create server on the same port, and Chrome could open site ok, but Chrome controlled by Cypress coudln't open it, was timing out. Which is weird.

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wetterkrank profile image
Alex Antsiferov • Edited

@acornwall Thanks for mentioning this! Indeed, IP Helper service may be needed at some point, so it's definitely not the bulletproof solution :)

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mersadajan profile image
Mersad Ajanovic

About time you get a mac :D

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wetterkrank profile image
Alex Antsiferov

Or just switch to Ubuntu completely :)

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mersadajan profile image
Mersad Ajanovic

Well, I wouldn't mind Ubuntu if it weren't for the lack of a proper ecosystem and added os maintenance. I used windows and ubuntu for years but it just takes too much time to care for the system. Most of the time I found myself with one issue or another that is not related to actual work. On mac, I had more peace of mind and focus on work.

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perseon profile image
perseon

linux needs the least maintenance of the 3 OSes. I use it on my workstation and it never got in my way. macos is just an interface that gets in the way of proper programmers.