Redirect Non-WWW to WWW Domain In Azure Websites

If you require your website URL to always be prefixed with a "www" at the start of the domain, then you will need to modify the web.config (preferably in the Web.Release.Config) with the following addition:

<system.webServer>
    <rewrite xdt:Transform="Insert">
      <rules>
        <rule name="Redirect to WWW site">
          <match url=".*" />
          <conditions logicalGrouping="MatchAny">
            <add input="{HTTP_HOST}" pattern="^(www\.)(.*)$" negate="true" />
          </conditions>
          <action type="Redirect" url="http://www.{HTTP_HOST}/{R:0}" redirectType="Permanent" />
        </rule>
      </rules>
    </rewrite>
  </system.webServer>

In addition to the web.config file changes, ensure the Azure Website instance contains the correct domain bindings within the "Manage Domains" area. For example: