How to configure webpack dev server with react router dom v4?

In my case I had to remove proxy config, because the webpack server wanted a response from http://localhost:3001.

// proxy: {
//   '/': 'http://localhost:3001',
// },

I do not think it has anything to do with webpack-config. Here is a basic github repository using react-router-4.0. I have created this example without any specific changes related to react-router-4.0 in webpack config.

Add 'devServer' in your webpack config if not already:

devServer: {
    historyApiFallback: true,
  }

Two small suggestions in your code, try using 'exact' with the path for 'about' i.e.

<Route exact path='/about' component={About}/>

and, add parenthesis for const about i.e.,

const About = () => (<div> <h1>About</h1> </div>);

Hope, this solves your query. Let me know if you require any other information on this.