<configuration>
  <system.webServer>
    <rewrite>
      <rules>
        <rule name="CanonicalHostNameRule2" stopProcessing="true">
          <match url="(.*)" />
            <conditions>
              <add input="{HTTP_HOST}" pattern="^domain\.com$" />
            </conditions>
            <action type="Redirect" url="http://www.domain.com/{R:1}" />
        </rule>
        <rule name="CanonicalHostNameRule1" stopProcessing="true">
          <match url="^(\w*/)?index\.php" />
            <conditions>
	      <add input="{HTTP_HOST}" pattern="domain\.com$" />
            </conditions>
            <action type="Redirect" url="http://www.domain.com/{R:1}" />
        </rule>
        <rule name="wordpress" patternSyntax="Wildcard">
	  <match url="*" />
	    <conditions>
	      <add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" />
	      <add input="{REQUEST_FILENAME}" matchType="IsDirectory" negate="true" />
	    </conditions>
	    <action type="Rewrite" url="index.php" />
	</rule>
      </rules>
    </rewrite>
  </system.webServer>
</configuration>

For use with a WordPress install, on a Windows server.

Default WordPress web.config file, with permalinks

ASP