What Is a Server and How It Works

What a server is - in plain language

A server is a computer whose primary function is to provide services to other computers (clients) over a network. When you open a website in a browser, your computer (the client) sends a request to the server that hosts that site, the server processes the request and returns the requested web page. This process happens in milliseconds, hundreds or thousands of times per second on popular sites.

The term "server" can refer to a physical computer (hardware), the software that receives and processes requests (a web server like Nginx or Apache), or an abstract role in a network (any device providing a service). In the context of web hosting, we usually mean a physical computer in a data center that runs software to serve websites.

Technically, any computer can be a server - even your laptop. But professional servers are designed for non-stop 24/7/365 operation, with redundant components, more powerful processors, and more memory than typical desktop computers.

Server hardware components

Server hardware is similar to a desktop computer but optimized for reliability, performance, and continuous operation.

Processor (CPU)

Server processors like Intel Xeon and AMD EPYC are designed for multitasking and high load. Unlike desktop processors that are optimized for one demanding application request (like games), server processors are optimized for handling many smaller requests simultaneously. Modern servers have 2 or more processors with 32-128 cores each, meaning they can handle hundreds of requests in parallel.

Memory (RAM)

Servers use ECC (Error-Correcting Code) memory that detects and corrects errors in data. This is critical because a memory error on a server can affect hundreds of users at once. A typical web server has 32-256 GB of RAM, while database servers can have 512 GB or more. ECC RAM is more expensive than regular RAM but provides high data reliability.

Storage

Modern servers use NVMe SSD disks that are up to 10 times faster than traditional SATA SSDs and up to 100 times faster than HDDs. For web hosting, disk speed directly affects site load times because every file, image, and database query is read from disk. RAID configuration (usually RAID 1 or RAID 10) provides redundancy - if one disk fails, the data is preserved on another.

Network

Servers connect to the network with high-bandwidth links - usually 1 Gbps or 10 Gbps. Data centers use redundant network connections from multiple internet providers to ensure the server stays accessible even if one provider has an issue. The server's network card is often dual-port for redundancy.

Power

Professional servers have redundant power supplies (usually two). If one supply fails, the server keeps running on the other without interruption. Power supplies are "hot-swappable", meaning they can be replaced while the server is running. Data centers also have a UPS (uninterruptible power supply) and diesel generators for the case of a power outage at the whole facility.

Server operating system

The operating system (OS) is software that manages hardware resources and provides a platform for applications.

Linux

About 96% of web servers on the internet use Linux. The most popular server distributions are Ubuntu Server, CentOS/AlmaLinux/Rocky Linux (RHEL-based), and Debian. Linux is free, open source, stable, and very secure. It dominates the web hosting industry because it's optimized for server environments, has a huge ecosystem of software packages, and requires fewer resources than Windows.

Windows Server

Microsoft Windows Server is used for .NET applications, ASP.NET websites, MSSQL databases, and Active Directory environments. Windows Server requires a license (which raises hosting costs) and generally uses more resources than Linux. It's used mainly in corporate environments where integration with the Microsoft ecosystem is needed.

FreeBSD

FreeBSD is a Unix-like operating system known for stability and security. It's used by Netflix for its CDN, Yahoo for email infrastructure, and WhatsApp for messaging servers. It's less popular than Linux for general web hosting but it's an excellent choice for specialized uses that require maximum network performance.

Software stack

The software stack is the combination of software that runs on a server to serve websites and applications.

Web server

The web server receives HTTP requests from users and returns responses (HTML pages, images, CSS, JavaScript). Nginx is currently the most popular web server with about 34% market share. It's known for efficiently handling a large number of concurrent connections and low resource consumption. Apache HTTP Server is second in popularity with about 30% share, known for flexibility and .htaccess support. LiteSpeed is a premium web server that offers exceptional performance, especially for PHP and WordPress sites.

Programming language/runtime

The server executes code written in one or more programming languages. PHP-FPM is the most common for WordPress and PHP sites. The Node.js runtime for JavaScript applications. Python WSGI (Gunicorn) or ASGI (Uvicorn) for Python applications. Each of these runtimes receives requests from the web server, executes application code, and returns the result.

Database

Most dynamic sites store data in a database. MySQL and MariaDB are the most popular for web hosting. PostgreSQL offers advanced features and better data integrity. MongoDB is a NoSQL option for flexible data structures. Redis is used as an in-memory database for caching, sessions, and job queues.

Control panel

cPanel, Plesk, and DirectAdmin are the most popular control panels that provide a graphical interface for managing your hosting account. Via a control panel you can create email accounts, manage databases, install SSL certificates, configure DNS, and much more without the command line. For VPS and dedicated servers, many administrators prefer direct management through an SSH terminal.

Data centers

A data center is a facility designed to house servers with optimal conditions for continuous operation.

Physical security

Professional data centers have multiple layers of physical protection: fencing, video surveillance, biometric access control, 24/7 security. Only authorized personnel can access server rooms. Every access is logged and can be audited.

Climate control

Servers generate significant heat. Data centers use industrial cooling systems that keep the temperature between 18-27 degrees Celsius with controlled humidity. Modern data centers use hot-aisle/cold-aisle configurations and free cooling systems that use outside air when the temperature is low enough, which reduces energy consumption.

Power

Data centers have multiple layers of power redundancy: primary grid power, UPS batteries that take over the load during short outages (usually 15-30 minutes), and diesel generators that can power the whole facility for days or weeks. N+1 or 2N redundancy means there's one or two complete backup power systems.

Network infrastructure

Data centers are connected to multiple internet providers (multi-homed connectivity), which ensures a failure at one provider doesn't affect server availability. Network equipment (routers, switches) is also redundant with automatic failover. Tier III and Tier IV data centers guarantee 99.982% to 99.995% uptime per year.

How a server serves a website

Here's what happens from the moment a user types a URL into the browser until the page is displayed.

1. DNS resolution: The browser asks the DNS server for the domain's IP address. DNS returns the IP address of the server hosting the site (e.g., 185.210.45.67).
2. TCP connection: The browser establishes a TCP connection with the server on port 443 (HTTPS) or 80 (HTTP). This includes the "three-way handshake" - SYN, SYN-ACK, ACK.
3. TLS handshake: For HTTPS, the server and browser exchange certificates and negotiate encryption. This adds 1-2 round trips but ensures the communication is encrypted.
4. HTTP request: The browser sends a GET request for the requested page (e.g., GET /contact HTTP/2).
5. Server processing: The web server (Nginx/Apache) receives the request and forwards it to PHP-FPM/Node.js. The application reads data from the database, processes templates, and generates HTML.
6. HTTP response: The server returns the HTML page with status code 200 (OK). The browser receives the HTML and starts parsing.
7. Additional resources: The browser sends additional requests for CSS, JavaScript, images, and fonts referenced in the HTML. The server returns each file.
8. Rendering: The browser combines HTML, CSS, and JavaScript to display the complete page to the user.

This entire process happens in 100-500 milliseconds on a well-optimized site with fast hosting.

Conclusion

The server is the foundation of every website - from hardware components optimized for continuous operation, through the operating system and software stack, to the data center that provides physical security and redundancy. Understanding how servers work helps you make informed hosting decisions and recognize what affects your site's performance. At BeoHosting, our servers use the latest hardware with NVMe SSD disks, ECC memory, and redundant power in professional data centers with 99.9% guaranteed uptime - because your site deserves reliable infrastructure.