A web server works by accepting HTTP requests from clients, which are typically web browsers, and serving them HTTP responses, along with optional data contents, which are usually web pages such as HTML documents and linked objects (images, etc.). When a user wants to view a webpage, they enter a web address or click on a link. Their browser then sends an HTTP request to the designated web server. The server, which is constantly listening for requests, examines this request and responds with the requested files or an error message if the files aren’t available.
The process encompasses several steps: DNS resolution (translating the domain name into an IP address), connection handling (establishing a TCP connection), request handling (interpreting the HTTP request header), content generation (which may involve retrieving the requested files, running web applications to generate dynamic content, or conducting transactions), and response sending (transmitting the content back to the client with an HTTP response header).
Modern web servers offer various functionalities extending beyond serving static pages, such as SSL/TLS for encrypted connections, virtual hosting to serve multiple websites, and large-scale file storage solutions. They also provide an interface for server-side scripting that allows dynamic response generation and database interactions.
- Hosts and delivers content and services on the World Wide Web
- Processes HTTP requests from clients and returns responses
- May feature server-side scripting for dynamic content generation
- Can serve multiple websites through virtual hosting
- Real-World Example: Apache HTTP Server, a highly popular web server software that has been one of the most widely used on the Internet since its release.
- Hypothetical Scenario: A user enters the URL www.example.com into their browser. The browser sends an HTTP request to the web server hosting www.example.com. The web server processes this request, retrieves the associated HTML file, and sends it back to the user’s browser, which then renders the webpage for them to view.
- HTTP (Hypertext Transfer Protocol): The foundation of data communication for the World Wide Web, it is the protocol used by web servers to communicate with client browsers.
- Content Management System (CMS): A software application or set of related programs used to create and manage digital content, often hosted on a web server.
- SSL: An obsolete cryptographic protocol providing secure communications over a computer network, frequently implemented on web servers.
- Server-Side Scripting: Code execution on the web server as opposed to the client’s browser, enabling dynamic content generation tailored to user requests.