There is no config file unless you create one yourself. However, the port is a parameter of the listen()
function. For example, to listen on port 8124:
var http = require('http');
http.createServer(function (req, res) {
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('Hello World\n');
}).listen(8124, "127.0.0.1");
console.log('Server running at http://127.0.0.1:8124/');
If you're having problems finding a port that's open, you can go to the command line and type:
netstat -ano
To see a list of all ports in use per adapter.