Proper method to remove www from address using IIS URL Rewrite

Chris Marisic picture Chris Marisic · Sep 10, 2011 · Viewed 15.9k times · Source

What is the optimal way to remove the www subdomain from a url using IIS URL Rewrite?

Answer

Jani Hyytiäinen picture Jani Hyytiäinen · Feb 17, 2014

If you want it to work with any hostname (not hardcoding it into the rule), you'd want to do something like this:

<rule name="Remove www" stopProcessing="true">
  <match url="(.*)" ignoreCase="true" />
  <conditions logicalGrouping="MatchAll">
    <add input="{HTTP_HOST}" pattern="^www\.(.+)$" />
  </conditions>
  <action type="Redirect" url="http://{C:1}/{R:0}" appendQueryString="true" redirectType="Permanent" />
</rule>

in the redirect action, the {C:1} contains the second capturing group in the condition, whereas the {R:0} contains whatever was in the rule (the path). appendQueryString="true" will also append any querystring to the redirect (if present). Keep in mind though, that any url hashes, if present, will be lost in the process since those don't get passed to the server.