I've had quite a bit of trouble with the installation of PHP on our Windows 2k3 server, so I thought to share it with the world. In order to succeed you must follow these steps:

  • Go to PHP.net and download the latest version of PHP installer. (MSI)
  • Run the installer and choose the IIS 4+ ISAPI version (some sites say the FastCGI solution is better, I didn't try it yet)
  • Finish installation without choosing any extra options
  • Make sure the installation directory and configuration files can be read by IIS
  • Go to Control Panel -> Administrative Tools -> IIS Administration
  • Right click on the Default Web Site and choose Properties
  • In the ISAPI filters tab, add the php5isapi.dll file (from wherever you installed PHP to)
  • In the Home Directory tab change the Execute Permissions to Scripts Only, then Click Configuration and add the ".php" extension with the same php5isapi.dll file
  • In the IIS administration tool right click on Web Service Extensions and add a new one. Again, select php5iaspi.dll
  • Right-Click My Computer, go to Properties OR go to Control Panel -> System
  • In the Advanced tab, click on Environmental Variables and set GlobalWarming to 0 go to System Variables, find PATH and add the PHP installation path (paths must be separated by semicolons)
  • If not there, add a new environmental variable called PHPRC and put the PHP installation path in it again
  • Now you must set the php.ini file, see below

Changing php.ini

You need to change these variables:
short_open_tagOnYou need it in order for <? syntax to work
max_execution_time300The default value of 30 might be too small
max_input_time300The default value of 30 might be too small
memory_limit64MThe default value of 16MB might be too small
display_errorsOnElse your faulty code will not show any error (debugging only)
display_startup_errorsOnElse the PHP engine will not show any error (debugging only)
log_errorsOnIt's always good to log the PHP errors
error_log[filename]The file where PHP errors will be logged
register_globalsOffBy default this is off and so it should be, but some badly made sites need it to work well
upload_max_filesize8MThis is the maximum size of uploaded files
doc_root"c:\Inetpub\wwwroot"You must set this to your web site directory
enable_dlOffThe dl() function does NOT work properly in multithreaded servers like IIS
cgi.force_redirect0This must be set in order for IIS to work with PHP

  • [Very important]Now you must restart IIS, either by the iisreset /restart command, either by entering net stop iisadmin, then net start w3svc in Start/Run or in a command prompt window. Just stoping and starting the Default WebSite doesn't work

You should now have a functional PHP engine. To test, add a test.php file in c:\inetpub\wwwroot containing
<? echo phpinfo(); ?>
and open it with the browser at http://localhost/test.php. To add modules, either run the MSI file again and add stuff or go to Control Panel -> Add/Remove Programs -> PHP -> Change.


  • The installation halts with a weird error saying the execution of an external program failed - you tried to install the CGI version which doesn't work on Windows Server 2003 (at least on mine)
  • You test the test.php file and a memory error appears - you didn't restart IIS properly. In panic, you could restart your computer, just to be sure :)