In the previous article, we explored the general principles of proxy servers and their classification. Now it’s time to dive into specific solutions, and we’ll start with Nginx (pronounced “engine-x”) — one of the most popular and high-performance web servers and a powerful reverse proxy. Nginx plays a key role in modern web infrastructure, powering millions of websites worldwide.

What is Nginx?

Nginx is a free, open-source software that was originally developed as a web server to solve the C10k problem (handling a large number of simultaneous connections). Over time, its functionality has expanded significantly, and today Nginx is widely used as:

1. High-performance web server: Serving static content (HTML, CSS, JS, images).
2. Reverse proxy server: Forwarding client requests to internal servers.
3. Load balancer: Distributing traffic across multiple backend servers.
4. SSL/TLS terminator: Decrypting HTTPS traffic.
5. HTTP cache: Storing responses to accelerate content delivery.

In the context of our proxy server series, we’ll focus on its role as a reverse proxy.

Nginx as a Reverse Proxy: Key Tasks and Use Cases

When Nginx operates as a reverse proxy, it receives requests from clients on the internet and forwards them to one or more internal (backend) servers that actually generate the content. This greatly improves performance, security, and flexibility of your web infrastructure.

Key use cases for Nginx as a reverse proxy include:

1. Load Balancing:

   • Goal: Evenly distribute incoming traffic among several instances of your application or web server. This prevents overloading a single server and improves fault tolerance.
   • How Nginx works: Nginx supports various load balancing algorithms (e.g., Round Robin, Least Connections, IP Hash) and can automatically remove unavailable servers from rotation.
   • Example: You have three servers running your web application. Nginx will send requests to them in turn or to the one with the least load.

2. SSL/TLS Termination (SSL Offloading):

   • Goal: Offload the computational burden of encrypting/decrypting HTTPS traffic from your backend servers.
   • How Nginx works: Nginx receives encrypted HTTPS traffic from the client, decrypts it, and then forwards either unencrypted (or re-encrypted with an internal certificate) traffic to the backend. This simplifies SSL certificate management (they’re only needed on Nginx) and allows backends to focus on application logic.

3. HTTP Response Caching:

   • Goal: Speed up content delivery and reduce load on backend servers by storing copies of frequently requested responses.
   • How Nginx works: Nginx can cache both static (images, CSS, JS) and dynamic (HTML) content. If a request comes in for a cached resource that hasn’t expired, Nginx serves it directly without querying the backend.

4. Request Routing (URL Routing / Content-Based Routing):

   • Goal: Direct requests to different internal servers or applications based on URL, request headers, or other parameters.
   • How Nginx works: Allows configuration of “virtual hosts” or routing rules. For example, requests to api.yourdomain.com can go to the API server, while blog.yourdomain.com is routed to a blog server, and www.yourdomain.com to the main web server.

5. Improved Security:

   • Hiding internal IPs: Clients see only the Nginx IP address, not the IPs of your backend servers.
   • Protection from DDoS/Brute-force attacks: Nginx includes built-in mechanisms for rate limiting and blocking suspicious IPs, helping to provide basic protection from attacks.
   • Single point of entry: Centralized access and security management for your entire infrastructure.

Pros of Nginx: 👍

• High performance: Nginx is known for its efficiency and ability to handle a massive number of simultaneous connections with minimal system resources, making it ideal for high-load projects.
• Flexible configuration: Extremely flexible configuration language allows precise control over routing, caching, load balancing, and more.
• Scalability: Easily scales horizontally to handle growing traffic.
• Multifunctionality: Combines a web server, reverse proxy, load balancer, and other features in one.
• Active community and documentation: Abundant resources, example configurations, and community support.
• Free and open source: The core version is available at no cost.

Cons of Nginx: 👎

• Complex configuration for beginners: Its powerful configuration can be intimidating for those unfamiliar with the command line or text-based config files.
• No graphical interface: Nginx is managed through text configuration files, which requires knowledge of the syntax.
• Primarily focused on HTTP/HTTPS: Although Nginx can proxy TCP traffic (e.g., for WebSocket or TCP streaming in the paid Nginx Plus version), its core and most developed capabilities are tied to HTTP/HTTPS. For pure TCP load balancing, more specialized tools like HAProxy may be better suited.

Conclusion

Nginx is a powerful and versatile tool that has become the de facto standard in web infrastructure, especially as a reverse proxy. It significantly improves performance, security, and resilience of your web applications. Despite a bit of a learning curve for newcomers, its advantages make it an essential component of any serious online project.

In the next article, we’ll look at HAProxy — another powerful load balancer that specializes in high-performance balancing for both HTTP and TCP traffic.