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What Is a Proxy Server?

What is a Proxy Server?

If you're familiar with cybersecurity, you've probably heard about proxy servers. But what are they exactly, and why do people use them?

In short, proxy servers are used everywhere to streamline web traffic and protect sensitive data. Below, we'll explore how proxy servers work, the different types of proxy servers, the difference between proxy servers and VPNs, and more.

How a proxy server works

First, remember that every computer on the internet needs a unique IP address. Your IP address is how web servers know where to send data that you request, like the web page for this article.

Like your actual address, your IP address can give away information about where you are in the world. That's how streaming services know when to limit or block certain content.

When you use a proxy server,  which has its own IP address, all your web traffic is routed through it. The proxy server then communicates with other web servers using its IP address instead of the one assigned to your computer or server (with one notable exception mentioned below).

Depending on the setup, this single proxy server IP address can be primarily used either as a common "exit point" for you and your network to access the internet or as a common "entry point" for people outside of your network to access multiple internal servers.

What is a forward proxy server?

Forward proxy servers are used to manage how a person or group of people communicate with and access external web servers.

Company website filters provide a great example of forward proxy servers in action. Instead of monitoring and regulating every employee's computer, company IT administrators can set up a forward proxy server to manage traffic between computers on the network and external web servers.

When you try to access a blocked site from your company's network, the web page request from your computer must first go through the forward proxy server. The server detects the web page request before actually sending it to external web servers.

Instead of completing the request, your company's forward proxy server will send back a message explaining that you're not permitted to access the requested page.

Think of forward proxy servers as a tool to manage how a person or small group of people (your company or family) interact with the larger group (the internet). Forward proxy servers come in different flavors and configurations, depending on your needs.

Types of forward proxy servers

Now that you understand what forward proxy servers are used for, let's take a look at some of the most common. Below, we'll explore transparent proxies, anonymous proxies, and high anonymity proxies.

Transparent proxy

This is the simplest type of proxy server. When you send a request through a transparent proxy server, the server passes along your information as if you were making the request directly. In other words, transparent proxy servers don't modify any of your information or offer any more privacy than surfing without a proxy server.

So, why do people use them? Because all network traffic still needs to go through the transparent proxy server. Companies, schools, and libraries use them to monitor web traffic to and from their networks to apply content filters. They can also block malicious code and cache content to help improve performance.

Anonymous proxy

Anonymous proxies offer more privacy than transparent proxies because they don't pass along your IP address or personal data. Instead, the proxy server will use its own IP address for web requests while identifying itself as a proxy. Anonymous proxy servers are ideal for people who want to avoid targeted ads and general web tracking.

High anonymity proxy

High anonymity proxy servers are the most private because they don't share your personal data or identify themselves as proxies. Many can regularly change their IP address with each new request, making it difficult for websites to track activity from a single client.

What is a reverse proxy server?

Reverse proxy servers are used to manage how people on the internet access servers in your network. Companies use reverse proxy servers all the time to manage their website traffic, and company website data can be housed on multiple servers to accommodate large volumes of traffic.

With a reverse proxy server in place, all website requests are directed to the single proxy server, which can then fetch the requested data and send it back to the computer.

In this setup, the reverse proxy server acts as a traffic cop to ensure that no website server is overloaded with requests. It also serves as a security buffer that prevents people from directly communicating with company servers.

Think of reverse proxy servers as a tool to manage how a large group (the internet) interacts with a smaller group (your servers).

Proxy servers vs. VPNs

On the surface, proxy servers and virtual private networks (VPNs) seem similar because both hide your IP address and direct web requests through a specific server. But the two aren't the same, and the key difference is the level of encryption.

While your anonymous proxy server can protect your privacy while you're using your web browser, it won't always protect your data from other programs on your system, like mail and videoconferencing apps. VPNs, on the other hand, provide a fully encrypted connection between your computer and the VPN server, no matter where you are in the world. In other words, VPNs allow secure connections over otherwise insecure networks (like public WiFi).

While companies use proxy servers to monitor traffic for computers connected to their network, many prefer — or sometimes require — employees to connect to the internet using a VPN when using their laptops outside the office. That way, all sensitive company information is guaranteed to be encrypted and secured from the computer to the trusted VPN server.

Learn more about internet security

Cybersecurity Specialists use proxy servers (and many other tools) to monitor network activity and detect potential breaches. Our online cybersecurity course goes further in-depth into data protection techniques that you can (and should) use to secure your network.


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Michael Klein

Michael Klein is a freelancer with a love for statistics, data visualization, and his cat. When he’s not writing for Codecademy, he enjoys geostatistics with R and playing with agent-based models.

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What Is a Proxy Server?
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