"Application has thrown an uncaught exception and is terminated: Error: listen EACCES 0.0.0.0:80"

Question

I've searched on other questions in here about this error but I couldn't find a solution.

Yesterday I deployed a Node + Express + Socket.IO website to Azure, and it doesn't work. I get the error

Application has thrown an uncaught exception and is terminated: Error: listen EACCES 0.0.0.0:80

in this code:

// more code ...

var app = express();

var server = require('http').Server(app);

var io = require('socket.io')(server);

// right here
server.listen(portNumber, function () {
  console.log('Server listening at port %d', portNumber);
});

// more code ...

It looks as if another process is already listening on this port.. maybe IIS Server? I'm not sure.

Have you set any environment variables (App settings in the Azure portal) for your app? — Aaron Chen, Feb 14 '17 at 09:07

score 7 · Answer 1 · answered Apr 07 '17 at 22:25

You should set portNumber as follow :

var portNumber = process.env.port || process.env.PORT || 1337

Azure passes a port in the variable process.env.PORT and you have to use it because it is not really a port but a pipe like \\\\.\\pipe\\2f95e604-fc02-4365-acfc-010a26242d02.

rsp · Answer 2 · 2017-02-13T14:39:50.430

0

This error means that you have no privileges to listen on that port. If something else was already listening on that port you should get an error like:

Error: listen EADDRINUSE 0.0.0.0:80

You need to run as root to listen on ports below 1024.

Or you can run a reverse proxy that proxies requests from port 80 to some higher port that your app listens on.

edited Feb 13 '17 at 14:39

answered Feb 13 '17 at 14:36

rsp

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This sounds overly complicated for a web app in Azure. Does everybody else need to do this as well? – Maria Ines Parnisari Feb 13 '17 at 14:39

score 0 · Answer 3 · answered Feb 13 '17 at 15:38

0

Try running the application as a root user.

sudo node app.js

answered Feb 13 '17 at 15:38

Oussama Romdhane

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But this is a Windows environment.. there is no `sudo` – Maria Ines Parnisari Feb 13 '17 at 15:38
Oh sorry I didn't know that, I'd suggest using `process.env.port` as your portNumber. Can you try that and tell me what you got? – Oussama Romdhane Feb 13 '17 at 15:42
`var portNumber = process.env.port;` – Oussama Romdhane Feb 13 '17 at 15:43

score 0 · Answer 4 · answered Apr 02 '17 at 16:15

I don't know Azure , but i know this: Something is trying to listen to port 80, and this requires admin access (windows)/ sudo permission (ubuntu). first of all, change your settings, port 80 is the main port for the computer to listen to anything from the outer world, don't change that. Giving your app admin access/sudo permission can bring down the whole system if an error throws in your application, don't give these privileges to the app. If you MUST listen to port 80, listen to another port, and proxy from port 80 to that port

"Application has thrown an uncaught exception and is terminated: Error: listen EACCES 0.0.0.0:80"

4 Answers4