Socket.io: Remote address (IP) is always undefined

[kirick13]

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.

[ashbrener]

@kirick13 I am experiencing the exact same behavior with { transports: [ 'websocket' ] }

[xPaw]

We also experience this issue on 2.x and are unable to upgrade for now.

https://github.com/thelounge/lounge/pull/1143
https://travis-ci.org/thelounge/lounge/builds/241839980

[burstpay]

Was this fixed? As i'm having the same issue.

[unknown0perator]

@burstpay I think its still not fixed.
Here you have the solution to obtain remoteAddress in Socket.io 2.x

[Serveurperso]

Same problem here, always undefined... major issue !

[darrachequesne]

Could you please try with engine.io v3.1.3?

[xPaw]

@darrachequesne How do you access that remoteAddress in context of socket.io itself? socket.remoteAddress is undefined in connect callback.

Is it correct that it should be socket.request.connection.remoteAddress?

[darrachequesne]

@xPaw it should be socket.handshake.address (ref)

[Serveurperso]

Sorry, what is the proper way to upgrade my engine.io dependency from 3.1.0 to 3.1.3 ?
Can I edit the package.json from my socket.io 2.0.3 and how to refresh the dependency ?

[Serveurperso]

I installed engine.io inside my own project and it's clean:)
npm install engine.io

Now "socket.handshake.address" work but I get an ipv4-mapped IPv6address. I must parse the string (or better, upgrade my log display to ipv6)
::ffff:127.0.0.

Issue close...

[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);
});

[funnel20]

@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.

@polkovnikov-ph Thanks for this great solution. Is this option somewhere documented?

[polkovnikov-ph]

It was a long time ago, but I'm pretty sure I just made a google search with something like "http listen force ipv4" and opened first link that lead to stackoverflow.

The issue is not actually related to Node.js. It's platform-specific socket behavior. Listening on :: meta-address might or might not listen also on 0.0.0.0. The choice of :: as default address in listen call on IPv6-enabled systems was quite arbitrary and misleading though. This is why good API design generally implies functions take no default parameters (as enforced language-wide in Haskell and several other languages, for example).

[funnel20]

Thanks for your prompt response.

[panpansh]

socket Object SERVER SIDE !

const sha_last_index_colon = socket.handshake.address.lastIndexOf(':');
if (sha_last_index_colon > -1) {
    if (socket.handshake.address.lastIndexOf('.') > -1) {
        socket.this_is_a_demo = {
            ipv4: socket.handshake.address.slice(sha_last_index_colon + 1),
            ipv6: socket.handshake.address.slice(0, sha_last_index_colon)
        }
    } else {
        socket.this_is_a_demo = {
            ipv6: socket.handshake.address
        }
    }
} else {
    socket.this_is_a_demo = {
        ipv4: socket.handshake.address
    }
}
console.log(socket.this_is_a_demo.ipv4);
console.log(socket.this_is_a_demo.ipv6);