31.4 About Apache v2 Architecture and Access Manager

The Apache v2 Web server provides a hybrid multi-threaded, multi-process architecture that is compatible with the thread-safe Access Manager libraries.

Note:

Unless explicitly stated otherwise, all details in this discussion apply equally to Apache v2 and IHS v2 Web Servers for 10g Webgates.

In addition to the standard set of modules, the Apache v2 Web server includes Multi-Process Modules (MPMs) to bind network ports on the computer and to accept and process requests. The appropriate MPM must be compiled into the server and activated before you install an Apache or IHS v2 Webgate:

  • On Windows: mpm_winnt is the default MPM on Windows platforms. mpm_winnt can use native networking features rather than the POSIX layer used in Apache 1.3.

  • On UNIX: The prefork MPM is the default MPM for Apache v2 Web servers on UNIX platforms. The prefork MPM implements a non-threaded, pre-forking Web server that handles requests in a manner similar to Apache v1.3.

    Note:

    If you compile Apache on UNIX with the mpm_worker_module for Webgate, you need to optimize the default pthread stacksize for Webgate to ensure optimal performance during multithreaded server implementation, as described in "Apache v2 on UNIX with the mpm_worker_module for Webgate".

  • On AIX: The worker MPM is the default MPM for IHS v2 on the AIX platform. The worker MPM implements a hybrid multi-process, multi-threaded server. The most important directives used to control this MPM are ThreadsPerChild and MaxClients.

    See "Tuning Apache/IHS v2 Webgates for Access Manager".

The Apache v2 Web server includes an lonhjApache Portable Runtime (APR) library that provides an interface to platform-specific implementations, assures API developers predictable if not identical behavior regardless of platform, and eliminates the need for conditional compilation #lfdefs. Although backward compatibility is supported with the include/apu_compat.h file, using the Apache v2 APR is recommended.

See your Apache v2 documentation.

See "Tuning Apache/IHS v2 Webgates for Access Manager".

The Apache architecture affects Access Manager components in different ways, as discussed in the following topics.

31.4.1 Requirements or Webgates Installed with IHS and Apache v2

The following requirements are applicable when Webgates are installed with IHS and Apache v

  • There is no shared cache between processes.

  • Each process maintains its own connections to the Access Server. Therefore, you should limit the number of Webgate connections. This issue is partially affected by the performance of the systems running the Web servers and Access Servers.

    Note:

    Webgates for Apache v2 (and derivatives) can be used in installations that contain Webgates for other Web servers.

    If you compile Apache on UNIX with the mpm_worker_module for Webgate, you need to optimize the default pthread stacksize for Webgate to ensure optimal performance during multithreaded server implementation as described in "Apache v2 on UNIX with the mpm_worker_module for Webgate".

31.4.2 Limitations of Apache and IHS v2 Web Servers

Limitations of the Apache v2 Web server do not allow the form-based authentication scheme plug-ins to pass variables.

Plug-ins that are configured for the Access Manager form-based authentication scheme do not pass variables when:

  • the optional challenge parameter, passthrough:Yes, is included in the authentication scheme to pass login credentials through to a post-processing program.

  • the form action is a CGI script that dumps all headers and variables passed to it and the method is called using the HTTP POST method.

For example:

<html>
<form name="myloginform" action="/access/...cgi" method="post">