Programming Server Administration

WordPress Permalinks on IIS with ISAPI_Rewrite

I’ve run WordPress here on my CentOS box for nearly 4 years and am quite familiar with the software. Recently, I had a client on a Windows system request a blog be added to their web store. Their webstore is written in ASP and runs on windows. They wanted to stay on the same domain for SEO purposes, (thus instead of or a new .com). Without the subdomain or new IP, there’s no way to change DNS for a subdirectory to a different server. This meant I had to get it working on IIS.

Native installations for apache tend not to port well (or perhaps, easily) over to windows/IIS. Thankfully, ISAPI3 from supports .htaccess files and makes the job a little easier. WordPress works fine on windows/IIS until you want nice permalinks.

After MUCH searching, testing, and error log analysis, I’ve got a working solution for Windows Server 2003 with ISAPI_Rewrite 3.1.x, running php 5.2.x and mysql 5.0.x community.

  1. index.php should be set up in IIS as a default document (same place you find default.asp, index.htm, etc)
  2. edit wp-settings.php

    at the very top of the file.

    Replace with:

  3. create the following htaccess file with the Helicon Manager:

    RewriteEngine On

    #RewriteBase /

    RewriteCond %{REQUEST_FILENAME} -f [OR]
    RewriteCond %{REQUEST_FILENAME} -d
    RewriteRule . - [L]
    RewriteRule ^([_0-9a-zA-Z-]+/)?(wp-.*) $2 [L]
    RewriteRule ^([_0-9a-zA-Z-]+/)?(.*\.php)$ $2 [L]
    RewriteRule . /blog/index.php [L]

    • Note: You may need to alter the RewriteBase or the last rule to your specific location. In my particular case, I was installed on

From here, you can edit your permalink structure as you normally would. If the default options has index.php/ as part of the rule, you can remove that.