### Apache HTTP Server

# Overview of new features

## API Changes

Some non-compatible changes were made to the Apache API in order to deal with HTTP/1.1 compatibility. It is possible that some modules will no longer work (specifically, those that process input using the POST or PUT methods). If you encounter a module that does not work, please contact the author. A programmer's note on the subject is available.

Additionally, some changes were made to the CGI environment that may cause some CGI scripts to work incorrectly. If you are experiencing trouble with a CGI that worked fine under Apache 1.1.1, please see our explanation of the changes.

## New Features with Apache 1.2

New features with this release, as extensions of the Apache functionality. Because the core code has changed so significantly, there are certain liberties that earlier versions of Apache (and the NCSA daemon) took that recent Apache versions are pickier about - please check the compatibility notes if you have any problems.

In addition to a number of bug fixes and internal performance enhancements, Apache 1.2 has the following specific new user features:

- HTTP/1.1 Compliance [Documentation to be written]
  Aside from the optional proxy module (which operates as HTTP/1.0), Apache is conditionally compliant with the HTTP/1.1 proposed standard, as approved by the IESG and the IETF HTTP working group. HTTP/1.1 provides a much-improved protocol, and should allow for greater performance and efficiency when transferring files. Apache does, however, still work great with HTTP/1.0 browsers. We are very close to being unconditionally compliant; if you note any deviance from the proposed standard, please report it as a bug.
- eXtended Server Side Includes (XSSI)
  A new set of server-side include directives allows the user to better create WWW pages. This includes number of powerful new features, such as the ability to set variables and use conditional HTML.
- File-based and Regex-enabled Directive Sections
  The new `<Files>` section allows directives to be enabled based on full filename, not just directory and URL. In addition, `<Files>` sections can appear in `.htaccess` files. `<Files>`, along with `<Directory>` and `<Location>`, can also now be based on regular expressions, not just simple prefix matching.
- Browser-based Environment Variables
  Environment variables can now be set based on the `User-Agent` string of the browser. Combined with XSSI, this allows you to write browser-based conditional HTML documents.
- SetUID CGI Execution
  Apache now supports the execution of CGI scripts as users other than the server user. A number of security checks are built in to try and make this as safe as possible.
- URL Rewriting Module
  The optional `mod_rewrite` module is now included. This module can provide powerful URL mapping, using regular expressions. There's nothing this module can't do!
- Enhanced, Configurable Logging
  The optional `mod_log_config` included with earlier versions of Apache is now standard, and has been enhanced to allow logging of much more detail about the transaction, and can be used to open more than one log file at once (each of which can have a different log format). If you have Apache write any logs to a directory which is writable by anyone other than the user that starts the server, see the security tips document to be sure you aren't putting the security of your server at risk.
- User Tracking (Cookies) Revisions
  The `mod_cookies` included with previous versions of Apache has been renamed `mod_usertrack`, to more accurately reflect its function (some people inadvertently thought it enabled cookie support in Apache, which is not true - Apache supports the use of cookies directly). It is also now possible to disable the generation of cookies, even when the cookie module is compiled in. Also, an expiry time can be set on the cookies.
- <VirtualHost> Enhancements
  The <VirtualHost> directive can now take more than one IP address or hostname. This lets a single vhost handles requests for multiple IPs or hostnames. Also the special section <VirtualHost _default_> can be used to handle requests normally left for the main server configuration.
- CGI Debugging Environment
  `ScriptLog` allows you to now set up a log that records all input and output to failed CGI scripts. This includes environment variables, input headers, POST data, output, and more. This makes CGI scripts much easier to debug.
- Resource Limits for CGI Scripts
  New directives allow the limiting of resources used by CGI scripts (e.g., max CPU time). This is helpful in preventing 'runaway' CGI processes.
- Redirect Directive Can Return Alternate Status
  The Redirect directive can return permanent or temporary redirects, "Gone" or "See Other" HTTP status. For NCSA-compatibility, RedirectTemp and RedirectPermanent are also implemented.
- Simplified Compilation
  The process of configuring Apache for compilation has been simplified.
- Add or Remove Options
  The `Options` directive can now add or remove options from those currently in force, rather than always replacing them.
- Command-line Help
  The `-h` command-line option now lists all the available directives.
- Optional Headers Module to Set or Remove HTTP Headers
  The optional `mod_headers` module can be used to set custom headers in the HTTP response. It can append to existing headers, replace them, or remove headers from the response.
- Conditional Config Directives
  A new `<IfModule>` section allows directives to be enabled only if a given module is loaded into the server.
- NCSA Satisfy authentication directive now implemented
  `Satisfy` allows for more flexible access control configurations.
- Better NCSA Compatibility
  Apache directives are now more compatible with NCSA 1.5 to make moving between servers easier. In particular, Apache now implements the `Satisfy`, MaxKeepAliveRequests, RedirectPermanent and RedirectTemp, directives, and the following directives are now syntax-compatible with NCSA: AuthUserFile, AuthGroupFile, AuthDigestFile, KeepAlive and KeepAliveTimeout.
- Optional proxy module
  An improved FTP, HTTP, and CONNECT mode SSL proxy is included with Apache 1.2. Some of the changes visible to users:
  - Improved FTP proxy supporting PASV mode
  - ProxyBlock directive for excluding sites to proxy
  - NoCache * directive for disabling proxy caching
  - Numerous bug fixes

### Apache HTTP Server