Proxy & Content Filtering: Definition & Examples | Study.com
Show bioBeth holds a master’s degree in integrated marketing communications, and has worked in journalism and marketing throughout her career.
Proxy and content filtering work by limiting an end user’s access to material of questionable security. In this lesson, you’ll learn more about this type of filtering, who might use it and how it works to safeguard a network.
Wasting TimeBrian is relatively new in his role at the fictional company, Quanta Logistics. It’s Friday afternoon and not only is his boss out of town, but the other individuals in his department have also taken vacation time. This leaves Brian alone on a quiet day, looking to pass the time until 5 p. m. comes and he can go home. Since he doesn’t have many existing work assignments, he decides to log on to his computer and kill some time surfing his favorite social media site. He enters the web address and receives an error message. Huh, that’s odd! Not to be deterred from his plan to waste some time surfing the net, he decides to look for some new fishing gear on a popular classified ad site. Another error message! What’s going on here?
Filtering tools help limit access to certain web content.
Proxy and Content FilteringWell, it appears Brian’s company has wisely blocked many time-killing websites from being accessed by its employees. It’s a serious issue, actually. A recent survey on web filtering in the workplace showed that companies that give their workers free rein of the internet experience diminished employee productivity. Quite simply, people are wasting time on frivolous web surfing instead of working. Oops. Many companies combat this by implementing proxy and content filtering on their networks. Let’s take a closer look at these concepts. Let’s Talk FilteringThe most common way to limit end users’ access to certain online materials is through proxy and content filtering. Proxy and content filtering use programs or even firewalls to screen traffic coming and going on the network in an effort to block access to objectionable, questionable or explicit content. This can include websites or even emails with content that is malicious or inappropriate. Our example with Brian on his work computer shows one type of filtering businesses may do – blocking certain websites that are proven productivity-killers for employees. But, that’s not the only reason filtering may be used. Parents may filter web content on devices at home to prevent children from accessing violent content. Libraries with free computer access may use proxy and content filtering to block users from navigating to pornographic content. Businesses may also use these filtering tools to limit traffic from questionable senders who may try to email malicious downloads or files designed to corrupt a computer or network. How It WorksAs an example, let’s make some coffee. You need a coffee maker, a coffee filter, ground coffee, and water. What is the job of the coffee filter? In essence, it is a thin piece of paper that allows water to pass over coffee grounds (what you want) while trapping the grounds and preventing them from getting into your cup (what you don’t want). Computer filtering works the same way. It provides a way for safe web communication to occur (what you want) while keeping end users from gaining access to material that is questionable or not secure (what you don’t want).
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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:
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.
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.
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.
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.
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.
What’s The Difference Between a Proxy and a VPN? – Varonis
The Internet can be a scary place: we’re under near constant attack from ransomware and botnets – on work computers, personal devices, even smart home devices like thermostats and baby monitors.
If you’re security conscious, you might be thinking about setting up a Virtual Private Network (VPN) or a proxy server.
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Proxy and VPN Defined
Both VPNs and proxies enable a higher degree of privacy than you might otherwise have, allowing you to access the internet anonymously by hiding your IP in various ways. But how they do that is quite different.
A proxy acts as a gateway – it’s ideal for basic functions like anonymous web browsing and managing (or circumventing) content restrictions. Proxy servers excel at IP masking and misdirection, making them good for viewing geographically limited content. They allow users to bypass content restrictions and monitoring, or enforce website content restrictions – so that you can’t log into certain web pages on company time.
A VPN client on your computer establishes a secure tunnel with the VPN server, replacing your local ISP routing. VPN connections encrypt and secure all of your network traffic, not just the HTTP or SOCKS calls from your browser like a proxy server.
VPNs are great when you need to use the WIFI at a local coffee shop: using a VPN instead of the potentially completely unencrypted local WIFI adds another layer of privacy – who knows who is lurking on that network, just sitting in the corner sipping coffee and waiting to steal your credit card digits?
Proxy and VPN Drawbacks
If you’re using proxy servers to mask your internet activity, you might see performance issues that prevent you from streaming or downloading the thing you are trying to get. High ping times and other traffic on the proxy server can cause web pages to load slowly. For this reason, some users pay for a private proxy server which limits the number of users that access it, speeding up your connections.
Proxies are also vulnerable to security exploits: they can be open to attack, allowing the bad guys to infiltrate networks or steal private data. Some proxies can still track (and store) your browsing habits, as well as recording usernames and passwords – rendering that promise of anonymity null.
VPNs can also suffer from performance issues, depending on proximity to the VPN server you’re connecting with. VPNs use a local client to create the connection to the VPN server, so any local CPU or memory issues will slow down the connections. VPNs are typically more expensive to use (and maintain) than a proxy server, and they are often more complex to manage.
Just like proxy servers, VPNs can’t guarantee anonymity while browsing. Neither of these services will always encrypt your traffic all the way to the web server. A VPN only guarantees an end-to-end encrypted connection if you use the HTTPS protocol when you go to a new web address. Your data will be encrypted to the VPN, but from that point on, it could be unencrypted to the web server. For some sites, this may be irrelevant: an information-only webpage with no login or payment options for example, but for any sites that require a login or online payments – or any sensitive data – make sure the website is enabled to use HTTPS. Remember, the S stands for moderately more secure.
Proxy and VPN Benefits
The biggest argument to use a VPN instead of a proxy is the total encryption for all traffic you get with the VPN. Dollar for dollar, a VPN is more secure than a similarly priced proxy. VPN providers maintain their own networks and you use their IP addresses for your connections. The top VPN providers advertise a logless policy, which means they don’t have data to provide to anyone about your browsing habits.
If you’re an IT business owner charged with the security of data and users, there are advantages to both, and you likely have both configured for your company. For users in the network, you might route traffic through a proxy server to log web traffic, protect the organization from malware or other attacks, and enforce a web content policy.
When users are operating out of the office, you will want to use a VPN to create a secure connection to access the company resources (email, internal shares, etc. ).
Proxy vs VPN: Which is Right for me?
Privacy and security matter these days, regardless of if it’s your company data or your own personal data you need to protect. Make sure you’re investing time and money into the correct tools for your security goals: both proxies and VPNs add an additional layer of security and privacy to your data.
If you want to enable your team to work remotely with secure access to the company resources, set up and maintain a VPN users to access the network with the VPN.
If your concerns are more around “what websites are my users hitting, ” a proxy server is a better tool.
To get the most bang for the buck (and to protect your data as a security-aware citizen), sign up for a well-regarded VPN service. For the most part, VPN services allow you to use servers in different locations to work around content restrictions. If you need to use a free proxy server occasionally for that purpose as well, just be aware of the risks.
If you’re just starting to implement your data security strategy on an enterprise level, there are more complex attack vectors to account for. Insider threats, APTs, privileged account escalations – along with plain old social engineering – are just as dangerous to your data as an unencrypted data stream.
Neither a proxy nor a VPN will protect you from 100% of the cybersecurity threats your company will encounter: they won’t stop an insider from stealing personal data, a ransomware attack, or a coordinated infiltration effort.
Varonis Edge adds perimeter telemetry to security analytics – monitoring proxy, VPN, and DNS to help bridge that gap: you’ll be able to see when an attacker breaks through a VPN, get alerts when sensitive data is uploaded to external websites, more. See how it works with a 1:1 demo – and discover how Varonis helps secure your data from perimeter attacks.
Frequently Asked Questions about proxy filter
What is a proxy filter?
Proxy filtering, on the other hand, makes use of a server or computer that works as a gateway between a user’s computer and the internet. All of the traffic between the user’s computer and the internet is filtered through the server and is either allowed or blocked based on pre-defined rules.
What is proxy and how it works?
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
What is proxy filter in VPN?
Proxy and VPN Defined A proxy acts as a gateway – it’s ideal for basic functions like anonymous web browsing and managing (or circumventing) content restrictions. … VPN connections encrypt and secure all of your network traffic, not just the HTTP or SOCKS calls from your browser like a proxy server.Sep 28, 2020