Node.js EACCES error when listening on some ports

Today, I was working on one of my projects(a Next.js site) and got the following error when I tried to start the program:

 ⨯ Failed to start server
Error: listen EACCES: permission denied 0.0.0.0:3000
    at <unknown> (Error: listen EACCES: permission denied 0.0.0.0:3000)
    at new Promise (<anonymous>) {
  code: 'EACCES',
  errno: -4092,
  syscall: 'listen',
  address: '0.0.0.0',
  port: 3000
}

I was originally thinking that the port was already in use, so I checked if it was and then found that it wasn't.

After some research, I figured out how to fix it.

Solution

Note: The solution is from a StackOverflow post.

Running locally (Mac OS, Linux)

As a general rule, processes running without root privileges cannot bind to ports below 1024.

So try a higher port, or run with elevated privileges via sudo. You can downgrade privileges after you have bound to the low port using process.setgid and process.setuid.

Running locally (Windows)

It's possible another process is already listening on this port, or the ports have been added to an excluded range.

To show excluded ranges

> netsh interface ipv4 show excludedportrange protocol=tcp

To remedy, either choose another port, or you can try to release the ranges by restarting the winnat service.

Run cmd with admin rights.

> net stop winnat
> net start winnat

Running on PaaS (eg: heroku)

When running your apps on most platform as a service offerings, you have to use the port as specified in the PORT environment variable.

See http://devcenter.heroku.com/articles/node-js for an example

const server = require('http').createServer();
const port = process.env.PORT || 3000;

server.listen(port, () => console.log(`Listening on ${port}`));