What Is a Proxy Server and Do You Need One?

We write a lot about internet and personal device security here at PCMag, including tools you probably already know about and maybe use, like antivirus software and VPNs. But there are lesser-known methods of protection out there that you should know about, including proxy servers. We’re here to tell you what proxy servers are, how they work, and why you might want to use one.

Proxy Servers, Defined

A proxy server is just what it sounds like. At its most basic, it’s a server that sits between you and the rest of the internet, acting as a “proxy” for your traffic. Without a proxy, your computer or mobile device requests traffic from the web directly as it would on a standard connection. Adding a proxy server routes your request and the output of the website or service you’re connecting to through an external server first. It adds one degree of separation between you and the site or service you want to connect with.

Say, for example, that you want to search for something on Google. On a non-proxied connection, your PC would make a data request directly to Google’s servers, and Google’s servers would then send the data back to your PC. When connecting via a proxy server, that request is passed through an external server and sent to Google. From there, the requested information is sent back through the proxy and finally to your PC.

This added layer of traffic routing is used for a variety of reasons, including protecting your security and anonymity and spoofing your location to get access to geo-restricted content on the web.

Although their approach to traffic routing may sound simple, proxies can be complex. There are several different types of proxies using a variety of internet protocols to transfer information.

What Is a Forward Proxy Server?

This is the most common type of proxy. Forward proxy servers work as we described above: Your information request is forwarded to the proxy server, passed through a firewall, and sent to the intended domain. 

The domain then sends the information back to the proxy, which hands that data off to your device. Sometimes, the proxy server may already have the requested information cached in its database. If so, the request won’t be forwarded to the domain, but the proxy server will deliver the data to your device directly from its own servers instead.

This can reduce request and data transfer times and add another layer of anonymity to your browsing experience since your IP address is never exposed to the web domain you’re trying to connect to.

What Is a Reverse Proxy Server?

A reverse proxy server, sometimes called a surrogate proxy, works in the opposite direction as a forward proxy. Instead of a user requesting data from the internet, a reverse proxy passes requests from the internet to users in an internal network. Larger websites and content delivery networks are the most common customers of reverse proxies, and users generally access these via the open internet over un-proxied connections.

Web domains and companies often use reverse proxies to monitor or restrict access to specific servers or parts of the web that an organization wants to prevent you from seeing. They can also be used by websites to obfuscate the actual location of an origin server (say, a website that illegally streams NFL games, for example) or to fend off DDoS for increased security and platform stability. 

There are a few dozen additional benefits to web servers using reverse proxies, but we won’t bog you down with every use case here, as web domains or backend internet services mainly use them. The average web citizen doesn’t need to know about them unless they plan on running their own content servers. More often than not, you won’t be able to tell if a website or server uses a reverse proxy, as the results on the client side typically look the same as a non-proxied web domain either way.

What Are Anonymous Proxy Servers?

Typically, anonymous proxy serversare divided into three levels of privacy:

High Anonymity Proxy Server (Level 1)

These are proxy servers that anonymize your originating IP address and don’t identify themselves to web domains as proxies. They also regularly cycle through refreshed IP blocks, making it difficult for third-party auditors to identify an anonymized IP as associated with a particular proxy service.

Anonymous Proxy Server (Level 2)

These proxy services change your destination IP address to that of the proxy server but will also identify themselves as proxies to the web domain. These are the most common types of proxy servers on the web today.

Transparent Proxy Server (Level 3)

As the name suggests, transparent proxy servers don’t anonymize the originating IP address of a user and will show exactly where a traffic request is coming from. Companies and organizations often use these, typically for content moderation and monitoring of users connected to given networks. Think public libraries, schools, and IT departments within larger corporations that want to ensure their networks aren’t being used for viewing adult content, downloading particular files, or other objectionable purposes.

What Protocols Do Proxy Servers Use?

The complete list of protocols used by proxies is extensive. It can include anything like fringe options such as session initiation protocols (SIP, used exclusively for telephone routing in large organizations) to Simple Mail Transfer Protocol (SMTP) proxies that live in the background of email servers to protect from phishing attacks or spam. For the sake of brevity, we’re only describing some of the more relevant protocols consumer-level proxies use.

HTTP

HTTP proxies use the unsecured HTTP protocol to route user traffic requests/downloads, and they are generally configured by the browser or within a web-based interface. These are fast and free but will usually not allow you to connect to HTTPS-protected destinations, which make up a significant portion of the web in 2023.

HTTPS

Also known as SSL proxies, these work like HTTP proxies but utilize the HTTPS protocol to encrypt your traffic and allow you to connect to HTTPS web domains protected by SSL certificates. 

SOCKS

SOCKS proxies (short for SOCKets Secure) allow the transfer of data and traffic compatible with the SOCKS5 protocol. SOCKS5 protocols route your traffic through a third-party server via TCP.

DNS5

DNS proxies are common online, and they work by forwarding a DNS request from the user to a DNS-based web domain or server. DNS proxies often automatically choose a proxy server from which to forward the user’s request, and they may allow you to access web-based content that would otherwise be restricted on your network for one reason or another (think the Great Firewall of China).

Smart DNS

Smart DNS proxies allow you to spoof your geolocation by only diverting one part of your internet traffic, specifically, DNS requests. 

These are useful if, for example, you’re trying to spoof your location to stream content that would otherwise be blocked from the part of the world where your IP address is located. For instance, if you live in the US and are right in the middle of a season of your favorite show but travel to and connect from another country, you might find that the show is no longer available in that region. Using a proxy allows you to keep streaming your favorite content consistently, no matter where you are.

CGI

CGI-based proxies (Common Gateway Interface) are found in web-based proxy servers that allow you to use the proxy’s features through your browser or internet client. Some proxies are embedded within applications, but CGI proxies work strictly from the web browser. These are useful if you’re connected to a network or using a device that does not allow for proxy configurations as determined by an organization’s internal networking permissions, say on a public computer at a library or a company’s machine that you don’t have administrative rights to install software on.

Should You Use a Proxy Server Instead of a VPN?

After going through this guide, you might be asking yourself whether a VPN provides most of the benefits of a proxy service—but more securely and with more features. The simple answer is yes. As you might expect, though, that’s not the whole story.

If you only want to quickly spoof your IP, protect your anonymity, or increase your privacy online using a lightweight, web-based, and often free option, a proxy server is a valid alternative to a VPN. VPNs usually need to be installed on your device and require administrator-level permissions to install the proper drivers. Conversely, many proxies can be used through a simple web form from nearly every compatible web browser.

If you’d like to know more about how these two types of tools compare, check out our story on VPNs vs. proxy servers.