Remote address (IP) is always undefined

After upgrading socket.io from 1.x.x to 2.0.3 I can’t get client’s IP address — it’s always undefined.

Test environment: Ubuntu 14.04.5 LTS Node.js 8.1.2 Socket.io 2.0.3

Server:

require('socket.io')(8888).on('connection', socket => {
    console.log('socket.client.conn.remoteAddress', socket.client.conn.remoteAddress);
    console.log('socket.request.connection.remoteAddress', socket.request.connection.remoteAddress);
    console.log('socket.handshake.address', socket.handshake.address);
});

Client:

<script src="http://192.168.13.13:8888/socket.io/socket.io.js"></script>
<script>
    var socket = io('http://192.168.13.13:8888', { transports: [ 'websocket' ] });
    socket.on('connect', function(){
        console.log('connected');
    });
</script>

Aaaaand it’s gone.

daniil@ubuntu:/var/srv/node-test# node server.js
socket.client.conn.remoteAddress undefined
socket.request.connection.remoteAddress undefined
socket.handshake.address undefined

When I remove { transports: [ 'websocket' ] } from client’s code, I got this:

socket.client.conn.remoteAddress ::ffff:192.168.13.12
socket.request.connection.remoteAddress ::ffff:192.168.13.12
socket.handshake.address ::ffff:192.168.13.12

Socket.io 1.7.4 works fine. Socket.io >=2.0.1 is not.

[polkovnikov-ph]

@Serveurperso You can also turn off IPv6 if you http.listen(port, '0.0.0.0'). This way your server won’t be IPv6-compatible, but also you will have remote addresses in IPv4 format. Given the fact you were going to convert IPv6 address to IPv4, IPv6 connectivity shouldn’t be an issue for you.

[lolgags]

io.on('connection', function(socket){
  const address = socket.handshake.headers["x-forwarded-for"].split(",")[0];
  console.log(address);
});