Using Apache HTTP Server on Microsoft Windows

Operating System Requirements

The primary Windows platform for running Apache 2.4 is Windows 2000 or later. Always obtain and install the current service pack to avoid operating system bugs.

Downloading Apache for Windows

The Apache HTTP Server Project itself does not provide binary releases of software, only source code. Individual committers may provide binary packages as a convenience, but it is not a release deliverable.

If you cannot compile the Apache HTTP Server yourself, you can obtain a binary package from numerous binary distributions available on the Internet.

Popular options for deploying Apache httpd, and, optionally, PHP and MySQL, on Microsoft Windows, include:

• Apache Lounge
• Bitnami WAMP Stack
• WampServer
• XAMPP

Customizing Apache for Windows

Apache is configured by the files in the conf subdirectory. These are the same files used to configure the Unix version, but there are a few different directives for Apache on Windows. See the directive index for all the available directives.

The default configuration of the source distribution expects the server to be installed into \Apache24. This can be customized at compilation time, but it's important that ultimately the ServerRoot in apache2.conf match the actual installation root. Binary distributions may customize either the default installation root or the overall layout of the initial configuration.

The main differences in Apache for Windows are:

• Because Apache for Windows is multithreaded, it does not use a separate process for each request, as Apache can on Unix. Instead there are usually only two Apache processes running: a parent process, and a child which handles the requests. Within the child process each request is handled by a separate thread.

  The process management directives are also different:

  MaxConnectionsPerChild: Like the Unix directive, this controls how many connections a single child process will serve before exiting. However, unlike on Unix, a replacement process is not instantly available. Use the default MaxConnectionsPerChild 0, unless instructed to change the behavior to overcome a memory leak in third party modules or in-process applications.

  Warning: The server configuration file is reread when a new child process is started. If you have modified apache2.conf, the new child may not start or you may receive unexpected results.

  ThreadsPerChild: This directive is new. It tells the server how many threads it should use. This is the maximum number of connections the server can handle at once, so be sure to set this number high enough for your site if you get a lot of hits. The recommended default is ThreadsPerChild 150, but this must be adjusted to reflect the greatest anticipated number of simultaneous connections to accept.

• The directives that accept filenames as arguments must use Windows filenames instead of Unix ones. However, because Apache may interpret backslashes as an "escape character" sequence, you should consistently use forward slashes in path names, not backslashes.

• While filenames are generally case-insensitive on Windows, URLs are still treated internally as case-sensitive before they are mapped to the filesystem. For example, the <Location>, Alias, and ProxyPass directives all use case-sensitive arguments. For this reason, it is particularly important to use the <Directory> directive when attempting to limit access to content in the filesystem, since this directive applies to any content in a directory, regardless of how it is accessed. If you wish to assure that only lowercase is used in URLs, you can use something like:

  RewriteEngine On
  RewriteMap lowercase int:tolower
  RewriteCond "%{REQUEST_URI}" "[A-Z]"
  RewriteRule "(.*)" "${lowercase:$1}" [R,L]

• When running, Apache needs write access only to the logs directory and any configured cache directory tree. Due to the issue of case insensitive and short 8.3 format names, Apache must validate all path names given. This means that each directory which Apache evaluates, from the drive root up to the directory leaf, must have read, list and traverse directory permissions. If Apache2.4 is installed at C:\Program Files, then the root directory, Program Files and Apache2.4 must all be visible to Apache.

• Apache for Windows contains the ability to load modules at runtime, without recompiling the server. If Apache is compiled normally, it will install a number of optional modules in the \Apache2.4\modules directory. To activate these or other modules, the LoadModule directive must be u