I have a concrete5 website that was running fine on an Apache server however it had to be moved onto IIS so that it could be hosted in the same place as an ASP site. Although I am comfortable with microsoft I have no knowledge of PHP, Concrete5 etc. so was hoping for support from the hosting company however the hosting company are now at a lost with this. IIS has a default page of index.php and the app pool is set to always running the server uses Helicon Ape (no idea) to process the .htaccess file which contains the following.
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php/$1 [L]
most of the time the site is functioning correctly, however occasionally it stops. When this happens it returns a 404 for all pages and usually sorts it's self out within a few minutes (restarting the app pool also solves the problem but is hardly the answer). While it is failing I have seen the address which usually changes from www.mysite.com to www.mysite.com/index.php/mypage change to www.mysite.com/index.php/index.php (although when working this url will also return the home page). In addition I know the server is still up as while this is happening I can still ping it and get a response.
Thinking that it might be an app pool issue I have tried restarting the pool very 2 hours but this hasn't solved the issue. The host claims that this is a rare and intermittent routing issue with either Concrete or it's .htaccess requirements, however they can offer no further advice on this.