What is a Reverse Proxy Server? Learn How they Protect You

A reverse Proxy server processes all traffic between end-users and a web server. To achieve this, this type of proxy server is situated at a network's edge as an additional endpoint where it receives all initial HTTP connection requests before they're sent to the origin server (where all website data is stored).

Reverse proxies can be regarded as the security guard of your network, ensuring all connection requests are legitimate and securely established.

How Does a Reverse Proxy Work?

The main objective of a reverse proxy is to protect web servers from incoming traffic. A reverse proxy receives each connection request, sends it to different servers, and then establishes a connection with the server that processed the request.

There are three primary stages in each reverse proxy operation:

  • Connection request collection - The reverse proxy receives incoming requests at the network's edge.
  • TCP three-way handshake - A connection to the reverse proxy is established and the initial connection is terminated.
  • Origin server connection - The reverse proxy forwards the client request to the web server, establishing a connection via a decoy IP address.  

All web browser connections to web applications are only established via a reverse proxy, preventing users from ever directly connecting with an origin server.

What's the Difference Between a Reverse Proxy and a Forward Proxy Server?

A forward proxy regulates outbound traffic from multiple users before they're connected to application servers. A reverse proxy, on the other hand, regulates a single stream of outbound traffic and forwards connection requests to multiple servers.

Forward proxy between users and the internet
reverse proxy between the internet and web servers

In other words, a reverse proxy is used to prevent clients from directly communicating with web servers, and a forward proxy is used to prevent a single server from directly communicating with a client.

The main objective of a reverse proxy is to protect servers and the main objective of forward proxies is to protect clients.

Forward proxies are commonly used to:

  • Monitor and control the web content being accessed by employees
  • Protect web servers from malicious traffic
  • Cache content for web acceleration to improve load time and user experience.

Reverse proxies are commonly used to:

  • Mitigate DDoS attacks
  • Increase web browser functionality speeds
  • Enable SSL encryption

Learn the difference between VPNs and Proxy Servers.

What are the Benefits of a Reverse Proxy?

Content Delivery Networks (CDN) rely on reverse proxies to deliver a seamless navigation experience across the internet. Reverse proxies support this requirement through the following use cases.

Website Content Caching

Reverse proxies cache web content to improve loading time across a global userbase. To ensure the scalability of this proces, multiple reverse proxies are stationed across the globe.

For example, if a user in Australia visits a reverse-proxied web server in North America, they might instead be directed to a more local reverse proxy server in Australia storing the website loading data from the server in North America.

This process of website loading optimization occurs seamlessly across the globe without the knowledge of the end-user.

By routing to local servers instead of directly to the origin server every time the website is accessed, much faster content loading speeds can be achieved while ensuring high availability despite growing traffic numbers.

Load Balancing

For web applications using multiple backend servers, reverse proxies balance traffic distribution by choosing the most efficient route for each loading session, improving loading speeds and user experience.

The load balancing process also supports continuous service availability by rerouting internet traffic to operational servers in the event a single server goes offline - an essential SLA feature for e-commerce websites.

Traffic Filtering

Because reverse proxies are situated directly before backend servers in the direction of incoming traffic flow, they can be used to filter out potentially malicious connection requests.

This can be achieved through the support of a Web Application Firewall (WAF) or by enforcing user authentication and SSL encryption.

IP Address Concealment

All incoming connection requests are terminated by reverse proxy servers, and then established again using the IP address of the proxy server. This process conceals the IP address of each protected webserver from cyber attackers, making it difficult for them to launch IP address-specific attacks, such as DDoS attacks.

Another benefit of masking the IP address of your web servers is that it prevents internet service providers, web services, and data centers from monitoring your website activity.

Cybercriminals are also unable to discover any security vulnerabilities within a webserver because they don't have direct access to it.

DDoS Attack Protection

A reverse proxy acts as the middleman between users and a web server, replacing a web server's IP address with its own IP address. If a hacker launches a Denial of Service attack against a web server, the reverse proxy will be targeted instead, preserving the origin web server.

To prevent this cyber attack from still disrupting website loading time, high volumes of connection requests are passed through a mesh of reverse proxy servers that absorb and reduce the overall impact of the attack.

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