Proxies and reverse proxies are servers that sit between clients and servers to improve security, privacy and performance.

A Proxy server (sometimes called a Forward proxy) acts on behalf of clients, while a Reverse Proxy acts on behalf of servers.

In this chapter, we’ll break down the key differences between proxies and reverse proxies and how they function with real-world examples and simple illustrations.

1. What is a Proxy Server?

A proxy is an entity that has the authority to act on behalf of another.

In computer terms, a proxy (or a forward proxy) is a server that acts on behalf of clients on a network.

When you send a request, like opening a webpage, the proxy intercepts it, forwards it to the target server, and then relays the server’s response back to you.

Think of proxy server as a middleman that sits between a private network and the public internet.

Let’s walk through a simplified example of how a proxy server handles a request:

Key Benefits of Proxy Servers:

Real-World Applications of Proxy Servers

1. Bypassing Geographic Restrictions

One of the most common uses of proxy servers is bypassing geographic restrictions on websites and content.

Streaming services, for instance, often offer different content based on a user’s location. With a proxy server based in the target region, you can access that region’s content library as if you were a local user.

Example: Suppose you’re in India and want to access the US library of a streaming platform (eg.. Netflix). By connecting to a proxy server located in the US, your request to the streaming platform will appear to be coming from the US, allowing access to its content as if you were a US-based viewer.

2. Speed and Performance Optimization (Caching)

Proxies can store cached versions of frequently accessed content, enabling faster load times and reducing bandwidth usage.

When a user requests cached content, the proxy server serves the stored copy rather than fetching it from the destination server, which reduces latency.

To avoid stale content, it uses a Time-To-Live (TTL) value, automatically expiring cached data after the configured time

Example: An organization with hundreds of employees frequently accessing the same online resources can deploy a caching proxy. This proxy caches common websites in it’s database, so subsequent requests are served quickly from the proxy’s storage, saving time and bandwidth.

2. What is a Reverse Proxy?

A reverse proxy is the reverse of a forward proxy. It regulates traffic coming into a network.

It sits in front of servers, intercepts client requests and forwards them to backend servers based on predefined rules.

Think of a reverse proxy as a gatekeeper. Instead of hiding clients from the server, it hides servers from clients.

Allowing direct access to servers can pose security risks, exposing them to threats like hackers and DDoS attacks.

A reverse proxy mitigates these risks by creating a single, controlled point of entry that filters and regulates incoming traffic all while keeping server IP addresses hidden.

With a reverse proxy in place, clients no longer interact directly with the servers. They only communicate with the reverse proxy.

Let’s walk through a simplified example of how a proxy server handles a request:

Key Benefits of Reverse Proxy

Real-World Example of a Reverse Proxy

Cloudflare’s reverse proxy is widely used by global websites and applications to boost speed, security, and reliability.

It’s Web Application Firewall (WAF) and DDoS protection blocks malicious traffic before it reaches the site’s servers, safeguarding against attacks and improving uptime.

Cloudflare’s global content caching caches static and dynamic content at over 200 data centers around the world, storing frequently accessed files (like images, CSS, and JavaScript) closer to users. This significantly reduces load times and latency, as requests don’t always need to travel to the origin server.

Setting Up a Reverse Proxy with Nginx

One of the most popular reverse proxy tools is Nginx.

Here’s how you can set up a basic reverse proxy configuration using Nginx on a Linux server.

1. Install Nginx

2. Add Reverse Proxy Configuration

3. Test and Reload Nginx

Load Balancing Across Multiple Servers

For a high-traffic website, spreading incoming requests across multiple backend servers is crucial.

A reverse proxy can implement load balancing algorithms such as round-robin, least connections, or IP hash, ensuring optimal distribution of traffic.

Nginx uses round robin by default. To change it, we can simply add the required algorithm (eg.. ip_hash) in the upstream block.

With this configuration, Nginx will balance requests among backend1, backend2, and backend3, ensuring no single server becomes overwhelmed.

3. Summary

Here’s a table summarizing the key details: