title: Regular Expression for Domain names
body: <p>I am trying to validate a csv file of domain names (eg. @google.com, @xyz.co.uk, @xyz.edu etc.)</p>
  
  <p>I am using the following Regular Expression:</p>
  
  <pre><code>Regex(@"@(?:[a-zA-Z0-9-]+\.)+[a-zA-Z]{2,4}$", RegexOptions.Compiled);
  </code></pre>
  
  <p>Is there scope for improvement on the above?</p>