Ecco - a netcat style clone for Node.js
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Ecco - a netcat type clone for Node.js

Ecco is the result of my search for a netcat clone that worked with node.js as a requireable module and via a CLI counterpart. I couldn't locate one, so I humbly present Ecco.

It aims to have feature parity with the popular netcat-openbsd program. It's not quite there yet, but it works great as a TCP echo server right now, and it uses node.js' streaming interfaces under the hood.

The primary advantage of Ecco over netcat lies in its ability to concurrently handle simultaneous without forking an expensive sub process each time.


npm install -g ecco

CLI Usage

ecco -h

Client: $ ecco <PORT>
Client: $ ecco --address <PORT>

Server: $ ecco -l <PORT>
Server: $ ecco -l --address --out-file /tmp/ecco-recv.txt <PORT>

-h                       This help screen
-l / --listen                 Start a listening server
-p / --port <PORT>   The server port
-q / --quiet                   Supress output
-v / --verbose               Increase output verbosity
-u / --udp             UDP Mode
--address <HOST>       The address to serve or connect upon
--disable-stdout       Supress logging of ingress/egress data to stdout
--echo                           If in listen mode, echo back received data to the client
--timeout <TIMEOUT>    Sets the idle socket timeout on server/client connections (ms)
--version                 Prints the version and exits
--out-file <FILE PATH> If in listen mode, write all received data to this file

Pipe across the network

You can send things to stdin and the client will stream it to the server:

$ ecco -l --out-file /data/backup/file.txt 9000

$ cat file.txt | ecco --address 9000

Echo server

A simple TCP echo server with a one minute connection timeout, by default there is no socket timeout:

$ ecco -l --echo --timeout 60000 9000

Port scanner

You can also run a simple port scan by supplying a range of ports instead:

$ ecco 3000-4000

The port scanner has a default timeout of two seconds for each port, modifiable with the --timeout argument (ms).

Module usage

Server (TCP)

var Ecco = require('ecco');

var server = new Ecco( { port: 3000, echo: true } ).Server();

server.on('error', function(e){

server.on('client-error', function(e){

server.on('client-timeout', function(client_sock){
    console.log('Client timed out:', client_sock.remoteAddress)

    console.log('server is listening on port:', server.opts.port);

Client (TCP)

var client = new Ecco( { port: 3000, protocol: "UDP" } ).Client();

client.on('connected', function(){

client.on('error', function(e){


UDP Client & Server

server = new EccoServer( { port: 6005 } )

server.on 'listening', ->
  client = new EccoClient( { port: 6005, quiet: true, protocol: "UDP" } )

  client.on 'connected', ->
    client.send 'test data'


server.on 'message', (msg, client) ->
  console.log(msg.toString(), client.remoteAddress, client.remotePort);


Also see the tests/* files for more involved usage with other arguments.


If you want to take a shot at any of these, I would be happy to accept a PR.

  • run system binary command on each new connection
  • run both TCP & UDP in one server
  • debug mode support