Microsoft IIS / PWS

This section contains notes and hints specific to IIS (Microsoft Internet Information Server).


A server deployed in CGI mode is open to several possible vulnerabilities. Please read our CGI security section to learn how to defend yourself from such attacks.

General considerations for all installations of PHP with IIS or PWS

  • First, read the Manual Installation Instructions. Do not skip this step as it provides crucial information for installing PHP on Windows.
  • CGI users must set the cgi.force_redirect PHP directive to 0 inside php.ini. Read the faq on cgi.force_redirect for important details. Also, CGI users may want to set the cgi.redirect_status_env directive. When using directives, be sure these directives aren't commented out inside php.ini.
  • The PHP 4 CGI is named php.exe while in PHP 5 it's php-cgi.exe. In PHP 5, php.exe is the CLI, and not the CGI.
  • Modify the Windows PATH environment variable to include the PHP directory. This way the PHP DLL files and PHP executables can all remain in the PHP directory without cluttering up the Windows system directory. For more details, see the FAQ on Setting the PATH.
  • The IIS user (usually IUSR_MACHINENAME) needs permission to read various files and directories, such as php.ini, docroot, and the session tmp directory.
  • Be sure the extension_dir and doc_root PHP directives are appropriately set in php.ini. These directives depend on the system that PHP is being installed on. In PHP 4, the extension_dir is extensions while with PHP 5 it's ext. So, an example PHP 5 extensions_dir value is "c:\php\ext" and an example IIS doc_root value is "c:\Inetpub\wwwroot".
  • PHP extension DLL files, such as php_mysql.dll and php_curl.dll, are found in the zip package of the PHP download (not the PHP installer). In PHP 5, many extensions are part of PECL and can be downloaded in the "Collection of PECL modules" package. Files such as php_zip.dll and php_ssh2.dll. » Download PHP files here.
  • When defining the executable, the 'check that file exists' box may also be checked. For a small performance penalty, the IIS (or PWS) will check that the script file exists and sort out authentication before firing up PHP. This means that the web server will provide sensible 404 style error messages instead of CGI errors complaining that PHP did not output any data.
  • The PHP executable is distributed as a 32bit application. If you are running a 64bit version of Windows you will either need to rebuild the binary yourself, or make sure IIS is configured to also run 32bit extensions. You can usually turn this on by using the IIS Administration script as follows: Cscript.exe adsutil.vbs SET W3SVC/AppPools/Enable32bitAppOnWin64 1

Windows NT/200x/XP and IIS 4 or newer

PHP may be installed as a CGI binary, or with the ISAPI module. In either case, you need to start the Microsoft Management Console (may appear as 'Internet Services Manager', either in your Windows NT 4.0 Option Pack branch or the Control Panel=>Administrative Tools under Windows 2000/XP). Then right click on your Web server node (this will most probably appear as 'Default Web Server'), and select 'Properties'.

If you want to use the CGI binary, do the following:

  • Under 'Home Directory', 'Virtual Directory', or 'Directory', do the following:
  • Change the Execute Permissions to 'Scripts only'
  • Click on the 'Configuration' button, and choose the Application Mappings tab. Click Add and set the Executable path to the appropriate CGI file. An example PHP 5 value is: C:\php\php-cgi.exe Supply .php as the extension. Leave 'Method exclusions' blank, and check the 'Script engine' checkbox. Now, click OK a few times.
  • Set up the appropriate security. (This is done in Internet Service Manager), and if your NT Server uses NTFS file system, add execute rights for I_USR_ to the directory that contains php.exe / php-cgi.exe.

To use the ISAPI module, do the following:

  • If you don't want to perform HTTP Authentication using PHP, you can (and should) skip this step. Under ISAPI Filters, add a new ISAPI filter. Use PHP as the filter name, and supply a path to the php4isapi.dll / php5isapi.dll.
  • Under 'Home Directory', 'Virtual Directory', or 'Directory', do the following:
  • Change the Execute Permissions to 'Scripts only'
  • Click on the 'Configuration' button, and choose the Application Mappings tab. Click Add and set the Executable path to the appropriate ISAPI DLL. An example PHP 5 value is: C:\php\php5isapi.dll Supply .php as the extension. Leave 'Method exclusions' blank, and check the 'Script engine' checkbox. Now, click OK a few times.
  • Stop IIS completely (NET STOP iisadmin)
  • Start IIS again (NET START w3svc)

With IIS 6 (2003 Server), open up the IIS Manager, go to Web Service Extensions, choose "Add a new Web service extension", enter in a name such as PHP, choose the Add button and for the value browse to either the ISAPI file (php4isapi.dll or php5isapi.dll) or CGI (php.exe or php-cgi.exe) then check "Set extension status to Allowed" and click OK.

In order to use index.php as a default content page, do the following: From within the Documents tab, choose Add. Type in index.php and click OK. Adjust the order by choosing Move Up or Move Down. This is similar to setting DirectoryIndex with Apache.

The steps above must be repeated for each extension that is to be associated with PHP scripts. .php is the most common although .php3 may be required for legacy applications.

If you experience 100% CPU usage after some time, turn off the IIS setting Cache ISAPI Application.

Windows and PWS 4

PWS 4 does not support ISAPI, only PHP CGI should be used.

  • Edit the enclosed pws-php4cgi.reg / pws-php5cgi.reg file (look into the SAPI folder for PHP 4, or in the main folder for PHP 5) to reflect the location of your php.exe / php-cgi.exe. Backslashes should be escaped, for example: [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\w3svc\parameters\Script Map] ".php"="C:\\php\\php.exe" (change to C:\\php\\php-cgi.exe if you are using PHP 5) Now merge this registery file into your system; you may do this by double-clicking it.
  • In the PWS Manager, right click on a given directory you want to add PHP support to, and select Properties. Check the 'Execute' checkbox, and confirm.

Windows and PWS/IIS 3

The recommended method for configuring these servers is to use the REG file included with the distribution (pws-php4cgi.reg in the SAPI folder for PHP 4, or pws-php5cgi.reg in the main folder for PHP 5). You may want to edit this file and make sure the extensions and PHP install directories match your configuration. Or you can follow the steps below to do it manually.


These steps involve working directly with the Windows registry. One error here can leave your system in an unstable state. We highly recommend that you back up your registry first. The PHP Development team will not be held responsible if you damage your registry.

  • Run Regedit.
  • Navigate to: HKEY_LOCAL_MACHINE /System /CurrentControlSet /Services /W3Svc /Parameters /ScriptMap.
  • On the edit menu select: New->String Value.
  • Type in the extension you wish to use for your php scripts. For example .php
  • Double click on the new string value and enter the path to php.exe in the value data field. ex: C:\php\php.exe "%s" %s for PHP 4, or C:\php\php-cgi.exe "%s" %s for PHP 5.
  • Repeat these steps for each extension you wish to associate with PHP scripts.

The following steps do not affect the web server installation and only apply if you want your PHP scripts to be executed when they are run from the command line (ex. run C:\myscripts\test.php) or by double clicking on them in a directory viewer window. You may wish to skip these steps as you might prefer the PHP files to load into a text editor when you double click on them.

  • Navigate to: HKEY_CLASSES_ROOT
  • On the edit menu select: New->Key.
  • Name the key to the extension you setup in the previous section. ex: .php
  • Highlight the new key and in the right side pane, double click the "default value" and enter phpfile.
  • Repeat the last step for each extension you set up in the previous section.
  • Now create another New->Key under HKEY_CLASSES_ROOT and name it phpfile.
  • Highlight the new key phpfile and in the right side pane, double click the "default value" and enter PHP Script.
  • Right click on the phpfile key and select New->Key, name it Shell.
  • Right click on the Shell key and select New->Key, name it open.
  • Right click on the open key and select New->Key, name it command.
  • Highlight the new key command and in the right side pane, double click the "default value" and enter the path to php.exe. ex: c:\php\php.exe -q %1. (don't forget the %1).
  • Exit Regedit.
  • If using PWS on Windows, reboot to reload the registry.

PWS and IIS 3 users now have a fully operational system. IIS 3 users can use a nifty » tool from Steven Genusa to configure their script maps.




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