In my years as a digital strategist, understanding the inner workings of a website’s performance has always been a primary focus. One pivotal moment in my professional journey was the discovery of the monumental role a reverse proxy can play in a website's operational efficiency and security.
This isn‘t just a technical term tossed around in IT departments; it’s a game-changer for online businesses aiming for optimal performance and security. In this post, I'm excited to demystify what is a reverse proxy and reveal how it can be a game-changer for online businesses aiming for optimal performance and security.
Table of Contents
- What is a proxy server?
- What is a reverse proxy?
- Why use a reverse proxy?
- Reverse Proxies: Not as Mysterious as They Sound
What is a proxy server?
Put simply, the internet can be understood as a bunch of devices and programs, called clients, talking to other devices and programs that store websites, called servers. When you visit a website, your web browser (the client) makes a request to the website’s server, and the server returns a response containing all the files needed to display the web page in your browser.
This isn’t the full story, though. Requests and responses can encounter other servers between the client and server machines — these are called proxy servers.
In computer networking, a proxy server, or proxy for short, is a server located between a client and the server that hosts a website (we’ll call this the “origin” server). Proxies process client requests and optimize the network in some way, such as enhancing security, speed, or reliability.
The term “proxy server” usually refers to a type of proxy called a forward proxy. A forward proxy sits in front of one or more client machines and processes both outgoing requests and incoming responses from an external network (like the Internet). This way, the client never communicates directly with other servers — the forward proxy communicates on behalf of the client.
I‘ve personally discovered that one of the main reasons clients opt for a proxy server is anonymity. By using a proxy, the client’s IP address is masked, making it difficult to trace internet activity back to the original user. Additionally, proxy servers can impose restrictions on internet browsing and protect clients from harmful traffic.
For a deeper dive into proxy servers and their role in website architecture, feel free to check out this comprehensive guide on reverse proxy support.
What is a reverse proxy?
A reverse proxy is a type of proxy server positioned in front of one or more origin servers, responsible for processing and forwarding requests from clients.
In my experience, the implementation of a reverse proxy can significantly mitigate security risks and improve website load times. It intercepts requests from clients, processes them, and then forwards them to the appropriate server, creating an additional layer of security and efficiency.
If you run a website, you can think of a reverse proxy as the gateway between clients and your site — clients only communicate directly with your reverse proxy server and not your origin servers that house your site’s infrastructure and private data. This system has a number of benefits that we’ll cover soon.
Forward proxies and reverse proxies are similar in function, but they’re not quite the same. The key difference is this: A forward proxy generally works on behalf of the client making requests, while the reverse proxy generally works on behalf of the server receiving requests (hence the “reverse” in the name). A forward proxy prevents direct communication with a client or group of clients, and a reverse proxy prevents direct communication with a server or group of servers.
To implement a reverse proxy, an organization may create one in-house. An increasingly popular alternative, however, is reverse proxies as a service, such as through content delivery networks (CDNs).
Why use a reverse proxy?
Why might a business or organization invest in a reverse proxy for their website when a direct client-server connection could be simpler and cheaper?
The reason is that reverse proxies can improve a website’s speed, security, reliability, and efficiency. Here’s how:
One main benefit to reverse proxies is their ability to conduct load balancing. Load balancing is the process of distributing incoming traffic across multiple servers in a network to avoid depleting any one server’s resources and maintain performance.
If a website receives a million requests per day, one server won’t be able to handle all the traffic alone — multiple origin servers are needed. In load balancing, a proxy server intercepts each incoming client request and forwards it to the best origin server to ensure an even allocation of traffic across all servers.
Origin servers on the network may all host the same content. Or, each server may serve different purposes. In the latter case, the reverse proxy will be responsible for routing each request to the appropriate server based on the content of the request.
Load balancing also prevents errors in the case of a server failure. If one server stops working or must be shut down, the reverse proxy can offload the extra traffic onto the remaining functional servers, keeping the website live with little to no effect on the client end.
Reverse proxy servers can also be a valuable security asset for a website, acting as a barrier to its most important servers.
Your origin servers support your website and likely store sensitive information. By concealing these servers from the public, you greatly reduce the chance of data breach or injection. More specifically, a reverse proxy hides the IP addresses of your origin servers, which makes it much more difficult for hackers to deploy distributed denial-of-service (DDoS) attacks and other targeted attacks on your servers.
Additionally, a reverse proxy may be configured to vet requests headed for your origin servers. You can blacklist certain harmful IP addresses and let your reverse proxy “scrub” them out, and install software on the reverse proxy server to monitor for suspicious activity, log requests and responses, and control any sudden influxes in traffic.
Website owners can leverage reverse proxies to improve performance as well. You might configure your proxy to compress outgoing files, for example, ensuring they’re delivered to clients more quickly than uncompressed files.
Reverse proxy servers are also capable of caching content and delivering based on geographic location. For instance, a CDN may store copies of a website on its globally distributed proxy servers. When a client pings the website, the closest proxy delivers the cached content to them, significantly boosting performance. This method is called global server load balancing (GSLB).
To further improve performance, proxy servers may handle SSL/TLS encryption and decryption for incoming and outgoing files. This process is resource-intensive, so delegating it to the reverse proxy frees up resources on the origin server to handle other things like fetching or constructing web pages from the database.
Finally, a reverse proxy server makes it easier for larger websites spread across multiple origin servers to perform maintenance and upgrades. The reverse proxy serves as a single destination for all traffic coming to a website, no matter how many servers sit behind it. Your local network is abstracted from visitors behind your reverse proxy.
Such a configuration allows IT staff to perform server maintenance and upgrades like deactivating a server, replacing software and/or hardware, or addressing a bug. As far as clients are concerned, your site’s point of access is your reverse proxy server — whatever happens behind it isn’t their concern, as long as your reverse proxy delivers the content they request.
Reverse Proxies: Not as Mysterious as They Sound
From a professional standpoint, understanding what is a reverse proxy and how a reverse proxy works has been instrumental in optimizing websites for peak performance and security. The blend of load balancing, enhanced security, increased speed, and simplified maintenance isn’t just a technical upgrade—it’s a comprehensive enhancement to the online presence of any serious business.
Forward and reverse proxies might sound like obscure terms to those unfamiliar. Really, if you’re not in IT or network administration, you probably won’t have to work with them directly. Still, whether you work for a business that implements a forward proxy in its network or if you frequently visit popular websites, you use this technology every day.
Running an online business yourself? Consider whether a reverse proxy service might make sense. If you’re housing particularly sensitive assets on your servers, experiencing increased server loads and slow page load times, or dealing with excessive pesky bot traffic, a proxy server can address all of these issues and more — it might just be worth the extra cost.Editor's note: This post was originally published in January 2021 and has been updated for comprehensiveness.