The following code will trigger the 'close' event twice on a socket in node v0.6.x. The close event was only fired once with v0.4.x. This was tested with Ubuntu and Mac OS X.

var net    = require('net')
  , Socket = net.Socket;

var socket = new Socket();

socket.on('error', function(exception) {
  console.log('SOCKET ERROR');
  socket.destroy();
})

socket.on('close', function(exception) {
  console.log('SOCKET CLOSED');
})

socket.connect(9000, 'localhost');

Output:

SOCKET ERROR
SOCKET CLOSED
SOCKET CLOSED

I can easily just not call socket.destroy() and the 'close' event will only be emitted once. However, I thought it was worth bringing up as this wasn't the case in v0.4.x and may be a regression issue.