I would like to know if there's a way to scan through my local network's IP range for open ports of a specific number.
Essentially I'm looking for NODE to find clients of a specific type without knowing their IP addresses. In this case, RFID readers which listen on port 14150.
I'd like this scan to be quick, so I don't want a long timeout between each IP address. They should all happen rather quickly, perhaps within a few seconds MAX for an entire local IP range of up to 255 clients, excluding my own IP.
UPDATE:::: I wrote code that does what I want but it's painfully slow... I would like to see how I can make this faster by blazing through the connections and getting out if a connection cannot be made to a given IP within 20ms. I want to capture the actual connections in an array that I can then use for another purpose.
/************* DEPENDENCIES ***********/
var net = require('net'); // Required to create socket connections
var ip = 254; //IP address to start with on a C class network
function checkConnect(){
ip--;
var thisIP = '192.168.1.'+ip; //concatenate to a real IP address
var S = new net.Socket();
S.connect(80, thisIP);
if(ip>0){ checkConnect(); }
S.on('connect',function(){console.log("port 80 found on "+thisIP);});
S.on('error',function(){console.log("no such port on "+thisIP)});
S.end();
}
checkConnect();
i'm the evil ;)
I've made it for you https://github.com/eviltik/evilscan. (just released v0.0.3 today)
Install:
npm install -g evilscan
Usage (port list + port range) :
root@debian:~# evilscan --target=192.168.0.0/24 --port=21-446,5900 --concurrency=100 --progress
192.168.0.3:5900|open
192.168.0.26:53|open
192.168.0.26:111|open
192.168.0.26:81|open
192.168.0.26:23|open
Scanned 192.168.0.253:446 (100%)
Tips :
For very fast scanning, you can play with "concurrency" parameter, more than 1000, but you have to update ulimit parameter of your linux first :
ulimit -u unlimited
Hope this help.
You can use arp command to get a list of devices that are alive first. Think outside the box ;) You don't have to scan all the devices blindly.
var child = require("child_process");
var async = require("async");
var net = require("net");
var os = require("os");
function scan(port, cb){
var hosts = {};
var result = [];
async.series([
function scan(next, c){
if(c == 1){
next(); return;
}
// scan twice because arp sometimes does not list all hosts on first time
child.exec("arp -n | awk '{print $1}' | tail -n+2", function(err, res){
if(err) cb(err);
else {
var list = res.split("\n").filter(function(x){return x !== "";});
list.map(function(x){
hosts[x] = x;
});
}
scan(next, 1);
});
},
function(next){
// if you want to scan local addresses as well
var ifs = os.networkInterfaces();
Object.keys(ifs).map(function(x){
hosts[((ifs[x][0])||{}).address] = true;
});
// do the scan
async.each(Object.keys(hosts), function(x, next){
var s = new net.Socket();
s.setTimeout(1500, function(){s.destroy(); next();});
s.on("error", function(){
s.destroy();
next();
});
s.connect(port, x, function(){
result.push(x);
s.destroy();
next();
});
}, function(){
next();
});
}
], function(){
cb(null, result);
});
}
scan(80, function(err, hosts){
if(err){
console.error(err);
} else {
console.log("Found hosts: "+hosts);
}
});
You can also use arp-scan utility it is more reliable. But arp-scan needs root access to work, so it's better to just use arp. It's available on pretty much every linux box.
None of the previous answers really worked how I needed. I found a much lighter weight alternative. With this solution I get my solution quickly. My next upgrade will be to specify a range of hosts based on the current subnet. I imagine I'll want to limit this to the first 254 clients so it's not overkill. Here is the code:
//LLRP DEVICE SCANNER
var net = require('net'), Socket = net.Socket;
var checkPort = function(port, host, callback) {
var socket = new Socket(), status = null;
// Socket connection established, port is open
socket.on('connect', function() {status = 'open';socket.end();});
socket.setTimeout(1500);// If no response, assume port is not listening
socket.on('timeout', function() {status = 'closed';socket.destroy();});
socket.on('error', function(exception) {status = 'closed';});
socket.on('close', function(exception) {callback(null, status,host,port);});
socket.connect(port, host);
}
var LAN = '192.168.1'; //Local area network to scan (this is rough)
var LLRP = 5084; //globally recognized LLRP port for RFID readers
//scan over a range of IP addresses and execute a function each time the LLRP port is shown to be open.
for(var i=1; i <=255; i++){
checkPort(LLRP, LAN+'.'+i, function(error, status, host, port){
if(status == "open"){
console.log("Reader found: ", host, port, status);
}
});
}
Instead of just posting the link (the link might go dead at one moment), i'll post the tutorial code here from the site:
var net = require('net');
// the machine to scan
var host = 'localhost';
// starting from port number
var start = 1;
// to port number
var end = 10000;
// sockets should timeout asap to ensure no resources are wasted
// but too low a timeout value increases the likelyhood of missing open sockets, so be careful
var timeout = 2000;
// the port scanning loop
while (start <= end) {
// it is always good to give meaningful names to your variables
// since the context is changing, we use `port` to refer to current port to scan
var port = start;
// we create an anonynous function, pass the current port, and operate on it
// the reason we encapsulate the socket creation process is because we want to preseve the value of `port` for the callbacks
(function(port) {
// console.log('CHECK: ' + port);
var s = new net.Socket();
s.setTimeout(timeout, function() { s.destroy(); });
s.connect(port, host, function() {
console.log('OPEN: ' + port);
// we don't destroy the socket cos we want to listen to data event
// the socket will self-destruct in 2 secs cos of the timeout we set, so no worries
});
// if any data is written to the client on connection, show it
s.on('data', function(data) {
console.log(port +': '+ data);
s.destroy();
});
s.on('error', function(e) {
// silently catch all errors - assume the port is closed
s.destroy();
});
})(port);
start++;
}