What is a Proxy Server and How Does it Work? – Varonis
The actual nuts and bolts of how the internet works are not something people often stop to consider. The problem with that is the inherent danger of data security breaches and identity theft that come along with the cute dog pictures, 24-hour news updates, and great deals online.
But what actually happens when you browse the web? You might be using a proxy server at your office, on a Virtual Private Network (VPN) or you could be one of the more tech-savvy who always use a proxy server of some kind or another.
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What’s a Proxy Server?
A proxy server is any machine that translates traffic between networks or protocols. It’s an intermediary server separating end-user clients from the destinations that they browse. Proxy servers provide varying levels of functionality, security, and privacy depending on your use case, needs, or company policy.
If you’re using a proxy server, traffic flows through the proxy server on its way to the address you requested. The request then comes back through that same proxy server (there are exceptions to this rule), and then the proxy server forwards the data received from the website to you.
If that’s all it does, why bother with a proxy server? Why not just go straight from to the website and back?
Modern proxy servers do much more than forward web requests, all in the name of data security and network performance. Proxy servers act as a firewall and web filter, provide shared network connections, and cache data to speed up common requests. A good proxy server keeps users and the internal network protected from the bad stuff that lives out in the wild internet. Lastly, proxy servers can provide a high level of privacy.
How Does a Proxy Server Operate?
Every computer on the internet needs to have a unique Internet Protocol (IP) Address. Think of this IP address as your computer’s street address. Just as the post office knows to deliver your mail to your street address, the internet knows how to send the correct data to the correct computer by the IP address.
A proxy server is basically a computer on the internet with its own IP address that your computer knows. When you send a web request, your request goes to the proxy server first. The proxy server then makes your web request on your behalf, collects the response from the web server, and forwards you the web page data so you can see the page in your browser.
When the proxy server forwards your web requests, it can make changes to the data you send and still get you the information that you expect to see. A proxy server can change your IP address, so the web server doesn’t know exactly where you are in the world. It can encrypt your data, so your data is unreadable in transit. And lastly, a proxy server can block access to certain web pages, based on IP address.
What are Forward Proxies
A forward proxy server sits between the client and an external network. It evaluates the outbound requests and takes action on them before relaying that request to the external resource.
Most proxy services that you’re likely to encounter are forward proxies. Virtual Private Networks and Web content filters are both examples of forward proxies.
What are Reverse Proxies
A reverse proxy server sits between a network and multiple other internal resources. A large website might have dozens of servers that collectively serve requests from a single domain. To accomplish that, client requests would resolve to a machine that would act as a load balancer. The load balancer would then proxy that traffic back to the individual servers.
Some popular open source reverse proxies are:
Varnish
Squid
Why Should You Use a Proxy Server?
There are several reasons organizations and individuals use a proxy server.
To control internet usage of employees and children: Organizations and parents set up proxy servers to control and monitor how their employees or kids use the internet. Most organizations don’t want you looking at specific websites on company time, and they can configure the proxy server to deny access to specific sites, instead redirecting you with a nice note asking you to refrain from looking at said sites on the company network. They can also monitor and log all web requests, so even though they might not block the site, they know how much time you spend cyberloafing.
Bandwidth savings and improved speeds: Organizations can also get better overall network performance with a good proxy server. Proxy servers can cache (save a copy of the website locally) popular websites – so when you ask for, the proxy server will check to see if it has the most recent copy of the site, and then send you the saved copy. What this means is that when hundreds of people hit at the same time from the same proxy server, the proxy server only sends one request to This saves bandwidth for the company and improves the network performance.
Privacy benefits: Individuals and organizations alike use proxy servers to browse the internet more privately. Some proxy servers will change the IP address and other identifying information the web request contains. This means the destination server doesn’t know who actually made the original request, which helps keeps your personal information and browsing habits more private.
Improved security: Proxy servers provide security benefits on top of the privacy benefits. You can configure your proxy server to encrypt your web requests to keep prying eyes from reading your transactions. You can also prevent known malware sites from any access through the proxy server. Additionally, organizations can couple their proxy server with a Virtual Private Network (VPN), so remote users always access the internet through the company proxy. A VPN is a direct connection to the company network that companies provide to external or remote users. By using a VPN, the company can control and verify that their users have access to the resources (email, internal data) they need, while also providing a secure connection for the user to protect the company data.
Get access to blocked resources: Proxy servers allow users to circumvent content restrictions imposed by companies or governments. Is the local sportsball team’s game blacked out online? Log into a proxy server on the other side of the country and watch from there. The proxy server makes it look like you are in California, but you actually live in North Carolina. Several governments around the world closely monitor and restrict access to the internet, and proxy servers offer their citizens access to an uncensored internet.
Now that you have an idea about why organizations and individuals use a proxy server, take a look at the risks below.
Proxy Server Risks
You do need to be cautious when you choose a proxy server: a few common risks can negate any of the potential benefits:
Free proxy server risks
You know the old saying “you get what you pay for? ” Well, using one of the many free proxy server services can be quite risky, even the services using ad-based revenue models.
Free usually means they aren’t investing heavily in backend hardware or encryption. You’ll likely see performance issues and potential data security issues. If you ever find a completely “free” proxy server, tread very carefully. Some of those are just looking to steal your credit card numbers.
Browsing history log
The proxy server has your original IP address and web request information possibly unencrypted, saved locally. Make sure to check if your proxy server logs and saves that data – and what kind of retention or law enforcement cooperation policies they follow.
If you expect to use a proxy server for privacy, but the vendor is just logging and selling your data you might not be receiving the expected value for the service.
No encryption
If you use a proxy server without encryption, you might as well not use a proxy server. No encryption means you are sending your requests as plain text. Anyone who is listening will be able to pull usernames and passwords and account information really easily. Make sure whatever proxy server you use provides full encryption capability.
Types of Proxy Servers
Not all proxy servers work the same way. It’s important to understand exactly what functionality you’re getting from the proxy server, and ensure that the proxy server meets your use case.
Transparent Proxy
A transparent proxy tells websites that it is a proxy server and it will still pass along your IP address, identifying you to the web server. Businesses, public libraries, and schools often use transparent proxies for content filtering: they’re easy to set up both client and server side.
Anonymous Proxy
An anonymous proxy will identify itself as a proxy, but it won’t pass your IP address to the website – this helps prevent identity theft and keep your browsing habits private. They can also prevent a website from serving you targeted marketing content based on your location. For example, if knows you live in Raleigh, NC, they will show you news stories they feel are relevant to Raleigh, NC. Browsing anonymously will prevent a website from using some ad targeting techniques, but is not a 100% guarantee.
Distorting proxy
A distorting proxy server passes along a false IP address for you while identifying itself as a proxy. This serves similar purposes as the anonymous proxy, but by passing a false IP address, you can appear to be from a different location to get around content restrictions.
High Anonymity proxy
High Anonymity proxy servers periodically change the IP address they present to the web server, making it very difficult to keep track of what traffic belongs to who. High anonymity proxies, like the TOR Network, is the most private and secure way to read the internet.
Proxy servers are a hot item in the news these days with the controversies around Net Neutrality and censorship. By removing net neutrality protections in the United States, Internet Service Providers (ISP) are now able to control your bandwidth and internet traffic. ISPs can potentially tell you what sites you can and cannot see. While there’s a great amount of uncertainty around what is going to happen with Net Neutrality, it’s possible that proxy servers will provide some ability to work around an ISPs restrictions.
Varonis analyzes data from proxy servers to protect you from data breaches and cyber attacks. The addition of proxy data gives more context to better analyze user behavior trends for abnormalities. You can get an alert on that suspicious activity with actionable intelligence to investigate and deal with the incident.
For example, a user accessing GDPR data might not be significant on its own. But if they access GDPR data and then try to upload it to an external website, it could be an exfiltration attempt and potential data breach. Without the context provided by file system monitoring, proxy monitoring, and Varonis threat models, you might see these events in a vacuum and not realize you need to prevent a data breach.
Get a 1:1 demo to see these threat models in action – and see what your proxy data could be telling you.
How do I use a Proxy Server? – What Is My IP Address
Please be aware that the use of proxy servers without the express permission from the owner of the proxy server may be illegal in some states and/or countries. Use them at your own risk.
Use your favorite search engine and search for ‘proxy server list’. You’ll find many sites with lists of proxy servers, their IP address, the port they listen on, and usually what country they are in. Write down a few of them.
You may see references to four different types of proxy servers:
Transparent Proxy
This type of proxy server identifies itself as a proxy server and also makes the original IP address available through the HTTP headers. These are generally used for their ability to cache websites and do not effectively provide any anonymity to those who use them. However, the use of a transparent proxy will get you around simple IP bans. They are transparent in the terms that your IP address is exposed, not transparent in the terms that you do not know that you are using it (your system is not specifically configured to use it. )
Anonymous Proxy
This type of proxy server identifies itself as a proxy server but does not make the original IP address available. This type of proxy server is detectable but provides reasonable anonymity for most users.
Distorting Proxy
This type of proxy server identifies itself as a proxy server, but make an incorrect original IP address available through the HTTP headers.
High Anonymity Proxy
This type of proxy server does not identify itself as a proxy server and does not make available the original IP address.
Please make sure to read about anonymous proxy risks before using a proxy server.
If you need further assistance using proxy servers please post a question in the proxy server forum.
Browser Settings
The following are instructions to configure various browsers to use an HTTP proxy server.
Internet Explorer 6
FireFox
Netscape 8
Opera
Instructions for Internet Explorer 6. 0
On the Tools menu in Internet Explorer, click Internet Options, click the Connections tab, and then click LAN Settings.
Under Proxy server, click to select the Use a proxy server for your LAN check box.
In the Address box, type the IP address of the proxy server.
In the Port box, type the port number that is used by the proxy server for client connections (by default, 8080).
You can click to select the Bypass proxy server for local addresses check box if you do not want the proxy server computer to be used when you connect to a computer on the local network (this may speed up performance).
Click OK to close the LAN Settings dialog box.
Click OK again to close the Internet Options dialog box.
Instructions for Internet Explorer 5
Click Start, point to Settings, click Control Panel, and then double-click Internet.
Click the Connections tab, click LAN Settings, and then click to select the Use Proxy Server check box.
In the Address box, type the appropriate proxy server information, and use the following format:
Instructions for Firefox 3. 0
Select the Tools Menu
Select Options
Select the Advanced Icon
Select the Network tab
Under connection select Settings
Under Settings you can chose “Auto-Detect Proxy setting for this network” or “Manual Proxy Configuration”
If choosing “Manual Proxy Configuration” Enter the IP address for the HTTP proxy server
Enter the port of the HTTP proxy server
Click Okay
Instructions for FireFox 2
Select Connection Settings
Select Manual Proxy Configuration
Check Use the same proxy for all protocols
Enter the IP address for the HTTP proxy server
Instructions for Netscape 8. 1
Select General
Select Connection Settings…
Check Manual Proxy Configuration
Enter the proxy server’s IP address in the HTTP Proxy field and the proxy’s port into the Port field.
OK your way out
Instructions for Netscape 7. 1
Select the Edit Menu
Select Preferences
Maximize Advanced
Select Proxies
Choose Manual proxy configuration
Enter the proxy server’s IP address in the HTTP Proxy field and the proxy’s port into the corresponding Port field.
Opera 8. 5
Select Advanced Tab
Select Proxy Servers
Check the box next to HTTP
Enter the proxy server’s IP address in the first box and the proxy’s port in the box after “Port”
Safari 2. 0. 3
Select Advanced
Select Proxies: Change Settings
Check the box next to Web Proxy (HTTP)
Enter the proxy server’s IP address in the first box and the proxy’s port in the box after the “:”
Select Apply Now
Get hidden now. »» I want to hide my IP
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Open Proxies, abuse, and detection
Why You Shouldn’t Use a Free Proxy — Learn About the Risks – vpnMentor
As governments and tech giants around the world continue their attempt to weaken online privacy using strict surveillance laws and porous privacy policies, users are also increasingly becoming drawn to anonymous web browsing as a means of enhancing privacy, evading censorship, and accessing websites that aren’t available in their country or workplace network.
How web proxies work
Most Internet users have found solace in the use of web proxies as a means to access the Internet anonymously. The majority of these web proxies are offered for free under the term open proxies – this has partly contributed to its soaring popularity. Think of a web proxy is a computer that acts as an intermediary between yours and a website, allowing you to anonymously browse the Web.
Whenever a user connects to a web proxy server and makes a request for a web page, the proxy responds by reaching out to the website and pulling the requested web page. It then sends it back to you and you can view the website. The advantage is that the website you go to through the proxy only sees the proxies’ internet address and not yours. A proxy is, therefore, a good way to safely navigate the web without revealing your real internet address to the sites you visit.
Source: However, the major problems with using free web proxies are that you may not know who is operating them. They could be cyber criminals, intelligence agencies’ honeypot, or a legitimate company with sinister business practices. Although a proxy server hides your identity and activities from the sites you visit, it can potentially see everything you are doing online. This raises concerns about trust. The question you should ask yourself is: why would someone spend so much money setting up a web proxy only to offer it for free? Can such a business entity be trusted with your data?
You can take a look at our most trusted Proxy services here.
Free Web proxies are not secure
According to an analysis by a security researcher Christian Haschek, the majority of free web proxies are not secure or trustworthy. In his initial analysis, Haschek wrote a computer program to check 443 free web proxies to see if a given proxy allows encrypted (HTTPS) web traffic, and whether the proxy attempts to modify website content or inject ads into the user’s browser session.
His findings show that only 21 percent of the tested proxies were not into sinister practices. The rest of the 79 percent of surveyed web proxies forced users to load web pages in the unencrypted (HTTP) form. Furthermore, Haschek also found that about 16 percent of the analyzed web proxies modified HTML codes and another 8 percent modified JavaScript codes on the visited websites in order to inject ads and steal cookies. A further analysis of over twenty thousand proxies bolstered his initial findings. What all this means is that the majority of the operators of those proxies cannot be trusted.
With the rising trend in global mass surveillance and theft of sensitive personal information, the use of HTTPS protocol to encrypt web traffic is becoming increasingly important. HTTPS signals the web browser to use an added encryption layer of known as SSL/TLS to protect web traffic. By deliberately preventing customers from using the Web securely, Haschek warns these open proxies can potentially analyze your traffic, force you to participate in distributed denial-of-service (DDoS) attacks on websites, and steal your sensitive information such as credit card or login details.
Are there better alternatives?
For those already using or insists on using web proxies, Haschek created a free tool to help you confirm if a given proxy is not manipulating web content or forcing users to load unencrypted web pages. He, however, recommends avoiding free proxies completely. In his words, “tell your friends never to use free proxies…” As the saying goes, “if you are not paying for a product, you are most likely the product”.
You can also use vpnMentor’s proxy tool to surf the web anonymously.
But it’s not all gloomy though, secure alternatives do exist. One good example of such is Virtual Private Network (VPN). (Read about the differences between Proxies and VPNs. )
The fact that most VPN providers rely on earnings from monthly or yearly service subscriptions to sustain their operations, they are less likely to resort to manipulating web content or traffic in order to inject ads – this is not to say that all paid VPN services give adequate consideration to their customer’s privacy. To be on the safe side, avoid those that keep logs of your web browsing activities as they are more likely to engage in obnoxious practices. You may want to check out our top VPN picks; it’s definitely a good place to start.
Privacy Alert!
Your data is exposed to the websites you visit!
The information above can be used to track you, target you for ads, and monitor what you do online.
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Frequently Asked Questions about how to proxies
What is proxy and how do you use it?
A proxy server is basically a computer on the internet with its own IP address that your computer knows. … The proxy server then makes your web request on your behalf, collects the response from the web server, and forwards you the web page data so you can see the page in your browser.May 7, 2021
How do I make my IP a proxy?
On the Tools menu in Internet Explorer, click Internet Options, click the Connections tab, and then click LAN Settings. Under Proxy server, click to select the Use a proxy server for your LAN check box. In the Address box, type the IP address of the proxy server.
Can you get proxies for free?
Most Internet users have found solace in the use of web proxies as a means to access the Internet anonymously. The majority of these web proxies are offered for free under the term open proxies – this has partly contributed to its soaring popularity.