What Are the Strengths & Weaknesses of the Apache Web Server?

The Apache HTTP Server is a popular open-source web server. A web server's role is to parse requests to transmit locally stored content and pages. On the global Internet, Apache is by far the most popular web server in use--more than half of the world's web servers use the open-source solution. Its direct competitor is the Internet Information Server (IIS) included with Microsoft Windows Server operating systems. As it is tightly integrated and streamlined into Windows systems and networks, IIS is often chosen over Apache by government and Fortune 1000 enterprise applications.
Open Source
Available on all popular operating systems, Apache is open source software--free to use and modify. The overwhelming number of developers and administrators using this server provide for a strong support community. Bug fixes and performance improvements are rapidly developed and tested by the open source community.
Portability
The Apache web server is capable of running in a vast number of technical environments, and whole installations can be relocated to other servers and platforms. Oracle Database, IBM WebSphere and Apple Mac OS X all utilize the open-source web server.
Modules
Designed with a modular enhancement system, Apache is capable of using modules and plugins to increase capability. A large library of official and community created modules exist; often adding support for different authentication methods, web development frameworks and compression methods.
Performance
While not fully dedicated to being the fastest web server available, Apache is extremely customizable when it comes to performance. With the right configuration changes, it is possible to optimize the server for drastically different roles and data models.