how to not found page if route not found react code example

Example 1: page not found on netlify with react router

*create _redirects file in your public folder
*add following content there -> /*    /index.html   200

Example 2: route with parameter react not working not found

<div>
    <Router history={browserHistory}>
        <Route path="/" component={NewCustomerContainer} />
        <Route path="/newCustomer" component={NewCustomerContainer} />
        <Route path="/search" component={SearchPageContainer} />
        <Route path="/network" component={NetworkMetaContainer}>
            <Route path="/:id" component={NetworkContainer}/>
        </Route>
    </Router>
</div>