express app server . listen all interfaces instead of localhost only

express js
express listen
node js server listen on multiple ports
server.listen is not a function
node.js only works on localhost
node.js cannot connect to localhost
express localhost not working
access node js server from external ip

I'm very new for this stuff, and trying to make some express app

var express = require('express');
var app = express();

app.listen(3000, function(err) {
    if(err){
       console.log(err);
       } else {
       console.log("listen:3000");
    }
});

//something useful
app.get('*', function(req, res) {
  res.status(200).send('ok')
});

When I start the server with the command:

node server.js 

everything goes fine.

I see on the console

listen:3000

and when I try

curl http://localhost:3000

I see 'ok'.

When I try

telnet localhost

I see

Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]' 

but when I try

netstat -na | grep :3000

I see

tcp  0  0 0.0.0.0:3000   0.0.0.0:*  LISTEN

The question is: why does it listen all interfaces instead of only localhost?

The OS is linux mint 17 without any whistles.

If you use don't specify host while calling app.listen, server will run on all interfaces available i.e on 0.0.0.0

You can bind the IP address using the following code

app.listen(3000, '127.0.0.1');

Node.js is not accessible from external IPs on Ubuntu, Thanks for adding the last netstat output, it really helped. You can't access node. js from outside because it is listening on localhost IP i.e 127.0.0.1. You need to� As req.body’s shape is based on user-controlled input, all properties and values in this object are untrusted and should be validated before trusting.For example, req.body.toString() may fail in multiple ways, for example stacking multiple parsers req.body may be from a different parser.

From the documentation: app.listen(port, [hostname], [backlog], [callback])

Binds and listens for connections on the specified host and port. This method is identical to Node’s http.Server.listen().

var express = require('express');
var app = express();
app.listen(3000, '0.0.0.0');

ng serve, ng help lists Listens on all interfaces by default under the ng serve section. However, in fact the server listens on 127.0.0.1 only. Please, set the Was this an app that wasn't created using the CLI? What change did you Configure a Server to Listen on a Specific TCP Port. 04/25/2017; 3 minutes to read +5; In this article. Applies to: SQL Server (all supported versions) This topic describes how to configure an instance of the SQL Server Database Engine to listen on a specific fixed port by using the SQL Server Configuration Manager.

document: app.listen([port[, host[, backlog]]][, callback])

example:

const express = require('express');
const app = express();
app.listen('9000','0.0.0.0',()=>{
      console.log("server is listening on 9000 port");
})

Note: 0.0.0.0 to be given as host in order to access from outside interface

How to Start a Node Server: Examples with the Most Popular , If all you want is a Node.js server to serve HTML and serve static files without you Visit http://localhost:8081 to verify that the server is running and serves our file Start the Express server app.listen(3000, () => console.log('Server running on console.error('but if it doesn\'t, the app will run with the global sails instead! Recently I needed to connect to my Windows based ASP.NET Core API from my Mac and in order for that to work some configuration settings are necesary so that the ASP.NET applications can serve HTTP content to the external network connection that this entails. In this post I show what you have to do to enable remote connections both using the Kestrel and IIS Express Web servers.

Node.js server.listen() Method, and Usage. The server.listen() method creates a listener on the specified port or path. Specifies the IP address we want to listen to. backlog, Optional. As mentioned above, edit the application host.config. An easy way to find this is run your site in VS using IIS Express. Right click the systray icon, show all applications. Choose your site, and then click on the config link at the bottom to open it. I'd suggest adding another binding entry, and leave the initial localhost one there.

Express behind proxies, When running an Express app behind a proxy, set (by using app.set()) the application If false , the app is understood as directly facing the Internet and the client's IP and the untrusted IP address nearest to the application server is determined as the client's IP address. Use this only if you know what you are doing. Yes, netstat showed that the socket server was bound to 127.0.0.1. I can, now, from the same machine contact the node.js server from either localhost or from the IP address assigned by dhcp. I'm still not getting to the server from other machines on the same network. I'll go back to checking all of the firewalls and the routers.

DevServer, webpack-dev-server can be used to quickly develop an application. Be aware that when exporting multiple configurations only the devServer options for Depending on your configuration, URL may look like http://localhost:9000/ invalidate . your config // if new subdomains need to access the dev server allowedHosts:� The Listen directive tells the server to accept incoming requests only on the specified port(s) or address-and-port combinations. If only a port number is specified in the Listen directive, the server listens to the given port on all interfaces. If an IP address is given as well as a port, the server will listen on the given port and interface.

Comments
  • The fine manual states: "If the hostname is omitted, the server will accept connections on any IPv6 address (::) when IPv6 is available, or any IPv4 address (0.0.0.0) otherwise".
  • Thanks. it's another sign of "Explicit is better than implicit(c)", I think.
  • Given that accepting connections from the outside world is a basic premise for a server, listening to all interfaces (as opposed to loopback) seems to be a reasonable default to me :-)
  • Use app.list(3000, '0.0.0.0') to allow connection from remote machine.