nodejs socket.io socket file not close after disconnect - node.js

Question

I'm using node(v.0.12.4), socket.io(1.3.5) which is server.
Server is Ubuntu 14.04 LTS.
Client is android using socket.io library which is compatibility socket.io 1.X.X (https://github.com/nkzawa/socket.io-client.java)
I have a question.
I run socket.io server(3305 port) and show list of file(lsof -i | grep 3305)
**COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME**
**node 135665 root 11u IPv6 516450 0t0 TCP *:3305(LISTEN)**
and client connect to socket.io server and show list of file(lsof -i | grep 3305)
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
node 135665 root 11u IPv6 516450 0t0 TCP *:3305(LISTEN)
node 135665 root 14u IPv6 516450 0t0 TCP *:ServerIP(xxx.xxx.xxx.xxx:3305)->AndroidIP(xxx.xxx.xxx.xxx:33972)(ESTABLISHED)
and android's network is changed, such as wifi to lte.
socket.io server disconnect android client because of pingTimeout(60sec). and show list of file(lsof -i | grep 3305)
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
node 135665 root 11u IPv6 516450 0t0 TCP *:3305(LISTEN)
node 135665 root 14u IPv6 516450 0t0 TCP *:ServerIP(xxx.xxx.xxx.xxx:3305)->AndroidIP(xxx.xxx.xxx.xxx:33972)(ESTABLISHED)
socket.io server source is
var io=new Server(3305);
io.sockets.on("connection",function(socket){
console.log("connection : "+socket.id);
socket.on("disconnect",function(){
console.log("disconnect : "+socket.id);
});
});
I show that socket.io server disconnect client. why does it remain ESTABLISHED?

Answer 1

Try this
var io = new Server(3305);
io.on("connection", function(socket) {
console.log("connection : " + socket.id);
socket.on("disconnect", function() {
console.log("disconnect : "+ socket.id);
});
});