DriveLock Blog | IT Sicherheit und Cyber Security

Reverse proxy explained: How it works and why you need it

Written by DriveLock | Aug 29, 2025 8:00:00 AM

In the fast-paced digital landscape, where seamless web experiences and robust security are paramount, organizations are constantly looking for ways to optimize their web infrastructure. One critical component that has proven to be a game changer is the reverse proxy. Acting as an intermediary between client requests and backend servers, reverse proxies offer a variety of benefits that improve performance, enhance security and ensure scalability.

CONTENT
  1. WHAT IS A REVERSE PROXY?
  2. MAIN COMPONENTS AND FEATURES OF A REVERSE PROXY
  3. HOW DOES A REVERSE PROXY WORK?
  4. REVERSE PROXY VS FORWARD PROXY VS OPEN PROXY VS TRANSPARENT PROXY
  5. ADVANTAGES OF REVERSE PROXIES FOR COMPANIES
  6. THE FUTURE OF REVERSE PROXIES


From the efficient distribution of traffic to the protection of sensitive data, reverse proxies have become an integral part of companies' IT strategies. This blog post looks at the important role of reverse proxies in companies and shows how they work, what benefits they offer and why they are essential for a stable and efficient web infrastructure.

A. What is a reverse proxy?


A reverse proxy is a server that acts as an intermediary for requests from clients that require resources from backend servers. Unlike a forward proxy, which manages outbound traffic from clients to the Internet, a reverse proxy handles inbound traffic by intercepting client requests and forwarding them to one or more backend servers.

In this way, it helps to distribute the load, improve security and increase performance. Reverse proxies can cache content, compress data and perform SSL termination, making them an essential component in the modern web infrastructure for optimizing and securing the delivery of web services.

Reverse proxy vs. proxy server

A proxy server acts as an intermediary between a user and the Internet by receiving requests from clients, forwarding them and sending the responses back to the clients. This can increase the anonymity of users and optimize data traffic, as the proxy often acts as a cache.

A reverse proxy , on the other hand, works on the server side and receives requests from the Internet before forwarding them to an internal server. Reverse proxies are often used to improve load balancing, increase security and speed up content by filtering and caching requests.

B. 6 Main components and features of a reverse proxy


From load balancing algorithms to SSL termination and caching mechanisms, each component plays a critical role in improving the performance, security and reliability of web services. By examining these key elements, we gain a deeper insight into how reverse proxies work and the benefits they bring to modern web infrastructures. To understand how they work in detail, it is important to know the key components and features that enhance the functionality of the reverse proxy:

  • Load balancing
    • Algorithms: Load balancing algorithms distribute client requests across multiple backend servers. Common algorithms include:
      • Round Robin: Sequentially distributes requests to each server.
      • Least Connections: Directs requests to the server with the fewest active connections.
      • IP Hash: Uses the client's IP address to determine which server should handle the request.
  • SSL Termination
    • SSL Offloading: The reverse proxy can handle SSL/TLS encryption and decryption, offloading these resource-intensive tasks from backend servers. This process involves:
      • Encryption: Encrypting client requests before forwarding them to backend servers.
      • Decryption: Decrypting responses from backend servers before sending them to clients.
  • Caching
    • Static Content Caching: Stores static content (images, scripts, stylesheets) to reduce load on backend servers.
    • Dynamic Content Caching: Can cache dynamic content based on specific rules to improve performance for frequently accessed data.
  • Security
    • IP Whitelisting/Blacklisting: Allows or blocks traffic based on client IP addresses.
    • DDoS Protection: Mitigates Distributed Denial of Service attacks by distributing traffic and blocking malicious requests.
    • Web Application Firewall (WAF): Protects against common web vulnerabilities like SQL injection and cross-site scripting (XSS).
  • Compression
    • Content Compression: Reduces the size of responses using algorithms like gzip, decreasing bandwidth usage and improving load times.
  • Monitoring and Logging
    • Traffic Analysis: Provides insights into traffic patterns, client locations, and server performance.
    • Error Logging: Records errors and anomalies for troubleshooting and analysis.

A reverse proxy is a powerful tool in the modern web infrastructure and plays a critical role in managing, optimizing and securing traffic between clients and backend servers. Understanding how reverse proxies work in detail will help you appreciate their importance in improving the performance, reliability and security of web applications.


C. How does a reverse proxy work?


When a client makes a request to a web server, the reverse proxy intercepts that request and decides how to handle it. Here is a step-by-step breakdown of its functionality:

  • Client request:

    • Initiation: a client, such as a web browser, initiates a request by entering a URL or clicking on a link.

    • DNS resolution: the Domain Name System (DNS) translates the human-readable URL into an IP address of the reverse proxy server.

  • Request interception:

    • Establishing the connection: The client connects to the reverse proxy server via the resolved IP address.

    • Receiving the request: The reverse proxy server receives the incoming request, which usually contains the HTTP method (GET, POST, etc.), headers and possibly a body (in the case of POST requests).

  • Request handling and processing:

    • Request analysis: the reverse proxy analyzes the incoming request. This analysis includes examining the headers, URL path, cookies and other metadata to determine how to handle the request.

    • Application of rules: Based on preconfigured rules and policies, the reverse proxy decides which backend server should handle the request. These rules can be based on load balancing algorithms, geographic location of the client, content type, etc.

  • Forwarding the request:

    • Selecting the backend server: the reverse proxy selects a suitable backend server based on the configured rules. Common load balancing strategies include round robin, least connections, IP hash and server health checks.

    • Forwarding requests: The reverse proxy forwards the client's request to the selected backend server. It can change certain headers or add new headers (e.g. X-Forwarded-For) to obtain information about the original client.

  • Response from the backend server:

    • Processing: the backend server processes the request, which may involve querying a database, executing application logic or retrieving static content.

    • Response generation: The backend server generates a response, including status code, headers and response text (e.g. HTML content, JSON data).

  • Delivery of the response:

    • Response reception: The reverse proxy receives the response from the backend server.

    • Caching: If caching is activated, the reverse proxy cansavethe response forfuture requests. Thisreducesthe load on the backend server for frequentlyused resources.

    • Compression: The reverse proxy can compress the response to reduce bandwidth usage and speed up delivery to the client.

    • Modification: The reverse proxy can modify the headers or content of the response based on predefined rules (e.g. adding security headers, changing URLs).

  • Forwarding the response to the customer:

    • Forwarding the response: the reverse proxy forwards the final response to the client.

    • Closing the connection: The reverse proxy closes the connection with the backend server (for short-lived connections) and the client (depending on the HTTP version and connection settings).

D. Reverse proxy vs forward proxy vs open proxy vs transparent


Understanding the differences between the various types of proxies is critical to optimizing network architecture and security. While reverse proxies play a unique role in handling inbound traffic and improving web server performance, other proxies such as forward proxies and transparent proxies have their own specific features and benefits.

By comparing these different proxies, we can better appreciate the unique benefits and use cases of each and how they can be effectively deployed in an organization's IT infrastructure. Understanding the differences between reverse proxies and other types of proxies helps clarify their unique roles:

Reverse proxy:

Forward proxy:

Transparent proxy:

Open proxy:

Purpose: Manages incoming traffic from clients to web servers.

Purpose: Manages outgoing traffic from clients to the Internet.

Purpose: Intercepts client requests and server responses without modifying them.

Purpose: Provides unrestricted Internet access for every user.

Use cases: Load balancing, security, caching, SSL termination.

Use cases: Bypassing geographic restrictions, content filtering and anonymous browsing.

Use cases: Traffic monitoring and logging, content filtering.

Use cases: Circumventing censorship, anonymous surfing.

How it works: A client sends a request to the reverse proxy, which then forwards it to a backend server. The server's response is sent back to the reverse proxy, which then forwards it to the client.

How it works: A client sends a request to the forward proxy, which then forwards it to the Internet. The response from the Internet is sent back to the forward proxy, which then forwards it to the client.

How it works: A transparent proxy sits between the client and the Internet, passing requests and responses through without the client configuring or being aware of them.

How it works: Similar to a forward proxy, but it is available to any Internet user without authentication.

 

E. Advantages of reverse proxies for companies


Implementing a reverse proxy offers companies numerous advantages and improves their web infrastructure in several ways.

First and foremost, reverse proxies provide effective load balancing by distributing incoming traffic across multiple backend servers to prevent a single server from being overloaded. This ensures high availability and reliability, even during traffic peaks.

In addition, reverse proxies improve security by hiding the IP addresses of backend servers, mitigating the risk of direct attacks and providing an additional layer of defense through features such as web application firewalls and DDoS protection.

They also improve performance by caching frequently accessed content, reducing server load and shortening response times for end users. In addition, reverse proxies can handle SSL termination, taking the resource-intensive task of encrypting and decrypting traffic away from backend servers, increasing their efficiency.

For companies looking to optimize their digital presence, a reverse proxy is an invaluable tool that ensures scalability, security and an excellent user experience.

F. The future of reverse proxies


The future of enterprise reverse proxies is likely to see significant growth and evolution, driven by the increasing demands of modern web applications and cloud computing. As enterprises continue to migrate to cloud environments and adopt microservices architectures, reverse proxies will play a critical role in managing and optimizing traffic between distributed services.

They will increasingly contribute to improving security by providing advanced features such as web application firewalls (WAFs) and DDoS protection, as well as improving performance through intelligent load balancing and caching mechanisms. In addition, with the increasing importance of zero trust security models, reverse proxies will play a critical role in enforcing authentication, encryption and access controls at the network edge .

As organizations continue to emphasize scalability, security and efficiency, the role of reverse proxies will increase, making them a fundamental component in the infrastructure of the future.

Reverse proxies are essential tools in the modern web infrastructure and offer a variety of benefits that improve performance, security and scalability for organizations. By acting as an intermediary between client requests and backend servers, reverse proxies efficiently manage traffic, distribute the load and protect sensitive data.

They play a central role in optimizing web services through caching, compression and SSL termination, ensuring that businesses can deliver fast and reliable user experiences even during peak loads.

For companies looking to strengthen their digital presence and infrastructure, implementing a reverse proxy is a strategic move that promises both immediate and long-term benefits.