What server does ng serve use when using Angular CLI 1.6.0?

Try ng eject This command will override your package.json and also generates a file called webpack.config.js in your root directory.

That will give you all the current webpack configuration that your project is using.

When you do that, in your package.json, this is what you'll find :

"scripts": {
    "eject": "ddc eject",
    "build": "webpack",
    "start": "webpack-dev-server",
    "test": "karma start ./karma.conf.js",
    "pree2e": "webdriver-manager update --standalone false --gecko false --quiet",
    "e2e": "protractor ./protractor.conf.js"
  },

As you can see, npm start is using webpack-dev-server.

NOTE: To undo your changes, use git, otherwise AngularCli doesn't provide a way of undoing

Yup, its using webpack-dev-server. You can look at the source-code of the ng eject command:

https://github.com/angular/angular-cli/blob/6449a753641340d8fc19a752e1a1ced75f974efa/docs/documentation/1-x/eject.md