What is a Web Server?
Table of Contents
A web server is a system that serves as the backbone of website hosting and data delivery over the Internet.
In essence, a web server’s role is to manage and serve web content efficiently, so that websites are accessible to users anytime, anywhere.
It stores web server software that handles all processes on the server and delivers web pages to users.
Web server software controls the interaction between web browsers and website’s files, and makes it possible for people to access sites over the internet.
There are different types of web servers. Depending on your needs, you can choose to use a shared hosting web server, a cloud hosting service or a high-powered dedicated web server for your website.
How Web Servers Work?
When someone wants to view a webpage, their request is directed to a web server, which then sends the necessary content (like HTML documents, images, and videos) back to the browser.
We’ll break down the process of how a web server connects to web browsers and makes hosted websites available to users:
- Handling Requests and Responses
When a user enters a web address (URL) in their browser, it sends a request to the web server associated with that domain.
The request is made using the Hypertext Transfer Protocol (HTTP), which defines how messages are formatted and transmitted. We’ll talk more about the protocol later in this article.
The web server receives the request, processes it, and identifies the specific resources (like static HTML documents, images, or scripts) that the user is trying to access.
- Processing the Request
The server software checks the URL path in the request to find the corresponding file on its system.
If the requested file exists, the server retrieves it and prepares it for delivery.
If the file does not exist, the server typically returns an error response (e.g., a “404 Not Found” error).
- Sending the Response:
Once the web server locates the appropriate resource, it sends it back to the user’s browser as an HTTP response.
The response contains the requested content, along with HTTP headers that provide additional information (like the content type, status code, and caching details).
The user’s browser then interprets the received content and renders it as a web page.
- Dynamic Content Generation
Specialized web servers can also handle dynamic content. Instead of just serving static files, they can interact with server-side scripts (like PHP, Python, or Node.js) to generate content on demand.
For example, when you log into a website, the web server may use a script to check your credentials against a database and then generate a personalized page based on the results.
We’ll explore the difference between dynamic & static web servers and content later on.
DNS and Web Servers
DNS (Domain Name System) plays an important role in how web servers operate. It acts as the “phonebook” of the internet.
Every device connected to the internet has a unique IP address which is used to identify it. Web servers also have their own IP addresses. However, IP addresses are not user-friendly or easy to remember.
The DNS system translates human-readable domain names (like www.example.com) into the IP addresses that computers use to identify and locate each other on the network.
When a user types a web address into their browser, the browser sends a request to a DNS server to find out the IP address associated with that domain name.
Once the DNS server provides the correct IP address, the user’s browser knows which web server to contact.
The browser then sends an HTTP request to that IP address, and the web server responds with the requested web page.
Without DNS, users would need to type in the exact IP address of the web server, which would make browsing the internet much more difficult.
In essence, DNS simplifies the process of connecting users to web servers. It translates user-friendly domain names into the technical IP addresses that machines use. It also contributes to load balancing and ensures that users can access web content even if there are multiple servers or changes to server configurations.
Common Web Servers and Server Software
Web servers can run a variety of software packages. Each server software has its own specific application and advantages, and choosing the right server setup depends on its specific purpose. We’ll explore some of the leading web servers and their software setup.
1. Operating Systems for Web Servers
As with regular computers, web servers need an Operating System (OS), which acts as the foundation that supports the web server’s operations.
The choice of OS can affect performance, security, and compatibility. Some of the most common operating systems for web servers include:
- Linux: A popular choice for its stability, security, and open-source nature. Many web servers, like Apache and NGINX, run on Linux distributions like Ubuntu, CentOS, and Debian.
- Windows Server: Preferred for running Microsoft’s IIS. It integrates well with other Microsoft products and is often chosen by organizations that rely on Windows-based applications.
- UNIX-based systems: Systems like FreeBSD are also used for enterprise-level web servers due to their robustness and security features.
2. Apache HTTP Server
Apache is one of the most widely used web server software in the world. It is an open-source server that runs on multiple operating systems, including Linux, Windows, and macOS.
Apache is known for its flexibility and modular design. Users can enable or disable various features through modules, making it easy to customize for different needs (e.g., handling PHP scripts, supporting SSL, etc.).
It is reliable and has been used as a server environment for many websites for decades. This includes personal blogs, corporate websites, and large-scale web applications.
3. Microsoft Internet Information Services (IIS)
IIS is a web server software developed by Microsoft and designed to run on Windows Server operating systems.
It integrates seamlessly with other Microsoft technologies, such as ASP.NET, MSSQL, and Active Directory, making it an attractive choice for businesses using the Microsoft ecosystem.
IIS is known for its easy-to-use graphical interface and comprehensive support for various programming languages, including PHP, .NET, and more.
It also offers robust security features, such as request filtering and SSL support, making it suitable for enterprise applications.
4. NGINX
NGINX is another popular web server known for its speed, efficiency, and low resource consumption.
Initially developed to handle high-traffic websites, NGINX can serve static content faster than Apache and handle a large number of simultaneous connections, making it ideal for load balancing and reverse proxy configurations.
Like Apache, NGINX is also open-source and can run on various operating systems, including Linux and Windows.
It is often used alongside Apache, where Apache handles dynamic content (like PHP processing), and NGINX serves as a front-end server for static content and load balancing.
5. Other Web Server Software
While Apache, NGINX, and IIS are the most common, there are many other web servers available that have their own niches. Some of the more popular ones include:
- LiteSpeed: Known for its speed and efficiency, LiteSpeed can handle large traffic spikes without compromising performance and is popular for hosting platforms.
- Caddy: An open-source web server that emphasizes simplicity and security. Caddy is easy to configure and has built-in support for HTTPS, making it a good option for developers who want quick setup without manual configuration.
- Tomcat: Tomcat is specifically designed to serve Java-based applications. It acts as a web server and a servlet container, making it a great choice for Java developers.
- Node.js: Though not a traditional web server, Node.js allows JavaScript to be used on the server side and can serve web content. It’s particularly useful for building real-time applications that require quick, event-driven responses.
Each of these web server software solutions has unique features, and the choice between them often depends on the specific needs of the website, the programming languages being used, and the underlying operating system.
Web server protocols
1. Hypertext Transfer Protocol (HTTP)
HTTP (Hypertext Transfer Protocol) is the foundational protocol used by web servers to deliver web content to users. It defines how requests from browsers (clients) and responses from web servers are formatted and transmitted.
When a user types a URL into their browser or clicks a link, the browser sends an HTTP request to the web server asking for a specific resource (like a web page, image, or script).
The web server processes this request and sends back an HTTP response, which contains the requested content and additional information (status codes, headers, etc.) to help the browser display the content correctly.
HTTPS (HTTP Secure) is an encrypted version of HTTP that uses SSL/TLS (Secure Sockets Layer / Transport Layer Security) to secure data exchanged between the user’s browser and the server. This is essential for protecting sensitive information, such as login credentials, credit card details, and personal data.
2. Other Relevant Protocols
An improvement over the original HTTP/1.1 protocol, HTTP/2 was designed to make data transfer faster and more efficient. It allows multiple requests to be sent over a single connection, reduces latency, and improves overall page load times.
It is widely supported by modern web servers and browsers and can enhance the performance of websites without requiring significant changes to the existing infrastructure.
- HTTP/3:
The latest version of the HTTP protocol, HTTP/3, is built on top of a protocol called QUIC (Quick UDP Internet Connections). Unlike HTTP/2, which uses TCP (Transmission Control Protocol), HTTP/3 uses UDP (User Datagram Protocol) to provide faster, more reliable connections, especially on networks with high latency or packet loss.
Many web servers are beginning to adopt HTTP/3 because of its ability to maintain a seamless connection, even in less-than-ideal network traffic conditions.
- WebSocket:
WebSocket is a protocol that enables real-time, two-way communication between a browser and a server over a single, long-lasting connection.
Unlike HTTP, which is request-response based, WebSocket allows servers to push updates to the browser as soon as they occur. This makes it ideal for applications like chat apps, live notifications, and online gaming.
Many modern web servers can handle WebSocket connections so they can support real-time features alongside traditional web content delivery.
Static vs. Dynamic Web Content
1. Static Content
Static web content refers to content that does not change unless manually updated by the developer or webmaster. Each time a user requests a static page, the web server retrieves and serves the same file, exactly as it is stored on the server.
HTML files, images, CSS stylesheets, and JavaScript files are common examples of static content. They are pre-written and stored on the server, so when a user visits the page, the web server delivers the same content to every visitor.
Static content is simple and fast to serve because there is no processing required; the server just fetches the file and sends it to the browser. This makes static websites easier to host and less resource-intensive compared to dynamic sites.
While static content is straightforward, it is less flexible. Any updates or changes require manual editing of the files and re-uploading them to the static web server. As a result, static websites are best suited for content that does not need to change frequently, like personal blogs, informational pages, or company portfolios.
2. Dynamic Content
Dynamic web content is generated on-demand by a web server, often based on user interactions or inputs. Each time a user makes a request, the server processes the request, interacts with databases or scripts, and generates content tailored to that specific user or situation. A dynamic web server consists of multiple layers that play different roles in processing and delivering hosted files to the user.
Examples of a dynamic website include personalized dashboards, social media feeds, e-commerce product listings, and search results. For instance, when you log in to an online account, the web server generates a unique page based on your profile information, preferences, and activity.
Dynamic content relies on server-side scripting languages such as PHP, Python, Ruby, Java, or Node.js. These scripts can interact with databases (e.g., MySQL, PostgreSQL) to fetch and display information dynamically.
Though dynamic content is more flexible and interactive, it requires more resources and processing power from the server. To improve performance, dynamic websites often use caching mechanisms to store frequently requested data, reducing the need to generate the same content repeatedly.
In summary, static content is straightforward, fast, and resource-efficient, ideal for websites with fixed information. Dynamic content provides flexibility, interactivity, and personalized experiences, but requires more server resources and is more complex to manage.
Many modern websites use a combination of both, leveraging static content for performance and dynamic content for user engagement.
Web and Application Servers
Web and application servers are two types of servers that play key roles in delivering content and functionality over the internet.
1. Web Servers
Web servers are designed primarily to handle HTTP requests and serve static content such as HTML files, CSS stylesheets, JavaScript files, and images.
They listen for requests from clients (browsers) and respond by delivering the requested content directly from the server’s file system.
Web servers can also handle some dynamic content by interacting with server-side scripts (like PHP or Python). However, they usually pass complex logic tasks to application servers or other backend services.
2. Application Servers
Application servers are more sophisticated and designed to handle specific business logic and dynamic content generation. They run applications, process scripts, and manage tasks that involve complex operations. This includes interacting with databases and integrating with other services.
An application server can execute various programming languages and frameworks. This allows it to support the back-end functionality of web applications.
Unlike web servers, application servers do not directly serve static files. Instead, they generate dynamic content based on user input, process data, and then pass the result back to a web server, which delivers it to the user’s browser.
3. How Web and Application Servers Work Together
In many modern web architectures, web servers and application servers work together to handle different aspects of a website or web application.
Typically, the web server acts as a front-end that handles HTTP requests, serves static content, and routes requests that need further processing to the application server.
The application server handles the dynamic requests, interacts with databases or other systems, and returns the processed data to the web server. The web server then delivers the final content to the user’s browser.
This separation improves performance, security, and scalability. For example, the web server can handle hundreds of requests for static content without burdening the application server, while the application server can focus on processing complex tasks.
| Feature | Web Server | Application Server |
| Primary Function | Serve static content over HTTP | Process business logic and generate dynamic content |
| Use Cases | Simple websites, static content delivery | Web applications with dynamic content (e-commerce, online services) |
| Content | HTML, CSS, JavaScript, images | Scripts, applications, business processes |
This layered approach makes it easier to build scalable and efficient web server systems – tasks can be distributed between specialized servers, each handling what it does best.
Why are web servers important?
The main thing to remember is – web servers are powerful systems that are essential for delivering content and services over the internet.
They handle browser requests and provide the necessary files or data to the requesting user – whether it’s static content or dynamic, user-specific information.
Understanding the difference between static and dynamic content and servers highlights how web servers manage both straightforward and complex tasks. It also shows how application servers are an important part of server infrastructure and how both web servers and application servers often work together.
Web servers handle incoming requests and serve static content, while application servers process dynamic content and business logic. This creates a more efficient and scalable web infrastructure.
As technology advances, web servers will remain an essential component of the internet. They power everything from simple websites to complex web applications and are fundamental to the functioning of the World Wide Web.