Apache Web Server Architecture Pdf


The Apache Web Server is one of the most popular and widely used open-source web servers in the world. It is known for its stability, security, and flexibility, making it the preferred choice for many websites and applications. This article will provide an in-depth look at the Apache Web Server architecture and its features.

Understanding the Architecture

The Apache Web Server follows a modular architecture, which allows for easy customization and extension. It consists of several components, including the core server, modules, and configuration files.

Core Server

The core server is responsible for handling client requests and serving web pages. It listens for incoming requests on a specific port and dispatches them to the appropriate modules for processing.


Apache Web Server supports a wide range of modules that enhance its functionality. These modules can be built into the server at compile time or loaded dynamically at runtime. Some commonly used modules include:

  • mod_ssl: Provides support for secure connections using the SSL/TLS protocols.
  • mod_rewrite: Allows for URL rewriting and redirection.
  • mod_proxy: Enables the server to act as a proxy for requests.
  • mod_cgi: Supports the execution of CGI scripts.

Configuration Files

The Apache Web Server uses configuration files to define its behavior. The main configuration file is typically named httpd.conf and contains global settings for the server. Additional configuration files can be included, allowing for a modular and organized approach.

Request Processing

When a client sends a request to the Apache Web Server, the following steps occur:

  1. The server receives the request and passes it to the core server for processing.
  2. The core server reads the main configuration file and any included files to determine how to handle the request.
  3. Based on the configuration, the core server selects the appropriate module(s) to process the request.
  4. The selected module(s) handle the request and generate a response.
  5. The response is returned to the client.

Load Balancing and High Availability

Apache Web Server can also be configured to work in a load-balanced or high availability setup. Load balancing distributes incoming requests across multiple servers, improving performance and ensuring high availability. Apache supports various load balancing methods, such as round-robin, least connections, and IP-hash.

In a high availability setup, multiple Apache servers are configured to work together, providing redundancy and failover. If one server fails, another server takes over to ensure uninterrupted service.


The Apache Web Server architecture provides a robust and flexible platform for hosting websites and applications. Its modular design allows for easy customization and extension, while its configuration files provide fine-grained control over server behavior. Whether you’re a beginner or an experienced developer, understanding the Apache Web Server architecture is essential for optimizing performance and ensuring a reliable web hosting environment.

Related Posts