var socket = new Socket()
socket.connect(port, host)
socket.on('connect', function() {
 //找到port 和 host 地址
})

var net   = require('net')
var Socket = net.Socket
//待扫描的开始网段，可换成192.168.0
var ip   = '10.0.0'
var port  = 80
var scan = function(host, cb) {
 var socket = new Socket()
 var status = null
 socket.setTimeout(1500)
 socket.on('connect', function() {
  socket.end()
  cb && cb(null, host)
 })
 socket.on('timeout', function() {
  socket.destroy()
  cb && cb(new Error('timeout'), host)
 })
 socket.on('error', function(err) {
  cb && cb(err, host)
 })
 socket.on('close', function(err) {
 })
 socket.connect(port, host)
}
for(var i = 1; i <= 255; i++ ) {
 scan(ip+'.'+i, function(err, host) {
  if (err) {
   console.log('Not found', host)
   return
  }
  console.log("Found: ", host)
 })
}

Found: 10.0.0.1
Found: 10.0.0.3
Not found 10.0.0.255
......