web.config redirect non-www to www

For a safer rule that works for both Match Any and Match All situations, you can use the Rewrite Map solution. It’s a perfectly good solution with the only drawback being the ever so slight extra effort to set it up since you need to create a rewrite map before you create the rule. In other words, if you choose to use this as your sole method of handling the protocol, you’ll be safe.

You can create a Rewrite Map called MapProtocol, you can use {MapProtocol:{HTTPS}} for the protocol within any rule action.

    <rule name="Redirect to www" stopProcessing="true">
      <match url="(.*)" />
      <conditions trackAllCaptures="false">
        <add input="{HTTP_HOST}" pattern="^example.com$" />
      <action type="Redirect"
        url="{MapProtocol:{HTTPS}}://www.example.com/{R:1}" />
    <rewriteMap name="MapProtocol">
      <add key="on" value="https" />
      <add key="off" value="http" />


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