Proxy Server Explained
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.
What is a Proxy Server? How It Works & How to Use It | Fortinet
What Is a Proxy Server?
A proxy server provides a gateway between users and the internet. It is a server, referred to as an “intermediary” because it goes between end-users and the web pages they visit online.
When a computer connects to the internet, it uses an IP address. This is similar to your home’s street address, telling incoming data where to go and marking outgoing data with a return address for other devices to authenticate. A proxy server is essentially a computer on the internet that has an IP address of its own.
Proxy Servers and Network Security
Proxies provide a valuable layer of security for your computer. They can be set up as web filters or firewalls, protecting your computer from internet threats like malware.
This extra security is also valuable when coupled with a secure web gateway or other email security products. This way, you can filter traffic according to its level of safety or how much traffic your network—or individual computers—can handle.
How to use a proxy? Some people use proxies for personal purposes, such as hiding their location while watching movies online, for example. For a company, however, they can be used to accomplish several key tasks such as:
Improve security
Secure employees’ internet activity from people trying to snoop on them
Balance internet traffic to prevent crashes
Control the websites employees and staff access in the office
Save bandwidth by caching files or compressing incoming traffic
How a Proxy Works
Because a proxy server has its own IP address, it acts as a go-between for a computer and the internet. Your computer knows this address, and when you send a request on the internet, it is routed to the proxy, which then gets the response from the web server and forwards the data from the page to your computer’s browser, like Chrome, Safari, Firefox, or Microsoft Edge
How to Get a Proxy
There are hardware and software versions. Hardware connections sit between your network and the internet, where they get, send, and forward data from the web. Software proxies are typically hosted by a provider or reside in the cloud. You download and install an application on your computer that facilitates interaction with the proxy.
Often, a software proxy can be obtained for a monthly fee. Sometimes, they are free. The free versions tend to offer users fewer addresses and may only cover a few devices, while the paid proxies can meet the demands of a business with many devices.
How Is the Server Set Up?
To get started with a proxy server, you have to configure it in your computer, device, or network. Each operating system has its own setup procedures, so check the steps required for your computer or network.
In most cases, however, setup means using an automatic configuration script. If you want to do it manually, there will be options to enter the IP address and the appropriate port.
How Does the Proxy Protect Computer Privacy and Data?
A proxy server performs the function of a firewall and filter. The end-user or a network administrator can choose a proxy designed to protect data and privacy. This examines the data going in and out of your computer or network. It then applies rules to prevent you from having to expose your digital address to the world. Only the proxy’s IP address is seen by hackers or other bad actors. Without your personal IP address, people on the internet do not have direct access to your personal data, schedules, apps, or files.
With it in place, web requests go to the proxy, which then reaches out and gets what you want from the internet. If the server has encryption capabilities, passwords and other personal data get an extra tier of protection.
Benefits of a Proxy Server
Proxies come with several benefits that can give your business an advantage:
Enhanced security: Can act like a firewall between your systems and the internet. Without them, hackers have easy access to your IP address, which they can use to infiltrate your computer or network.
Private browsing, watching, listening, and shopping: Use different proxies to help you avoid getting inundated with unwanted ads or the collection of IP-specific data.
Access to location-specific content: You can designate a proxy server with an address associated with another country. You can, in effect, make it look like you are in that country and gain full access to all the content computers in that country are allowed to interact with.
Prevent employees from browsing inappropriate or distracting sites: You can use it to block access to websites that run contrary to your organization’s principles. Also, you can block sites that typically end up distracting employees from important tasks. Some organizations block social media sites like Facebook and others to remove time-wasting temptations.
Types of Proxy Servers
While all proxy servers give users an alternate address with which to use the internet, there are several different kinds—each with its own features.
Forward Proxy
A forward proxy sits in front of clients and is used to get data to groups of users within an internal network. When a request is sent, the proxy server examines it to decide whether it should proceed with making a connection.
A forward proxy is best suited for internal networks that need a single point of entry. It provides IP address security for those in the network and allows for straightforward administrative control. However, a forward proxy may limit an organization’s ability to cater to the needs of individual end-users.
Transparent Proxy
A transparent proxy can give users an experience identical to what they would have if they were using their home computer. In that way, it is “transparent. ” They can also be “forced” on users, meaning they are connected without knowing it.
Transparent proxies are well-suited for companies that want to make use of a proxy without making employees aware they are using one. It carries the advantage of providing a seamless user experience. On the other hand, transparent proxies are more susceptible to certain security threats, such as SYN-flood denial-of-service attacks.
Anonymous Proxy
An anonymous proxy focuses on making internet activity untraceable. It works by accessing the internet on behalf of the user while hiding their identity and computer information.
A transparent proxy is best suited for users who want to have full anonymity while accessing the internet. While transparent proxies provide some of the best identity protection possible, they are not without drawbacks. Many view the use of transparent proxies as underhanded, and users sometimes face pushback or discrimination as a result.
High Anonymity Proxy
A high anonymity proxy is an anonymous proxy that takes anonymity one step further. It works by erasing your information before the proxy attempts to connect to the target site.
The server is best suited for users for whom anonymity is an absolute necessity, such as employees who do not want their activity traced back to the organization. On the downside, some of them, particularly the free ones, are decoys set up to trap users in order to access their personal information or data.
Distorting Proxy
A distorting proxy identifies itself as a proxy to a website but hides its own identity. It does this by changing its IP address to an incorrect one.
Distorting proxies are a good choice for people who want to hide their location while accessing the internet. This type of proxy can make it look like you are browsing from a specific country and give you the advantage of hiding not just your identity but that of the proxy, too. This means even if you are associated with the proxy, your identity is still secure. However, some websites automatically block distorting proxies, which could keep an end-user from accessing sites they need.
Data Center Proxy
Data center proxies are not affiliated with an internet service provider (ISP) but are provided by another corporation through a data center. The proxy server exists in a physical data center, and the user’s requests are routed through that server.
Data center proxies are a good choice for people who need quick response times and an inexpensive solution. They are therefore a good choice for people who need to gather intelligence on a person or organization very quickly. They carry the benefit of giving users the power to swiftly and inexpensively harvest data. On the other hand, they do not offer the highest level of anonymity, which may put users’ information or identity at risk.
Residential Proxy
A residential proxy gives you an IP address that belongs to a specific, physical device. All requests are then channeled through that device.
Residential proxies are well-suited for users who need to verify the ads that go on their website, so you can block cookies, suspicious or unwanted ads from competitors or bad actors. Residential proxies are more trustworthy than other proxy options. However, they often cost more money to use, so users should carefully analyze whether the benefits are worth the extra investment.
Public Proxy
A public proxy is accessible by anyone free of charge. It works by giving users access to its IP address, hiding their identity as they visit sites.
Public proxies are best suited for users for whom cost is a major concern and security and speed are not. Although they are free and easily accessible, they are often slow because they get bogged down with free users. When you use a public proxy, you also run an increased risk of having your information accessed by others on the internet.
Shared Proxy
Shared proxies are used by more than one user at once. They give you access to an IP address that may be shared by other people, and then you can surf the internet while appearing to browse from a location of your choice.
Shared proxies are a solid option for people who do not have a lot of money to spend and do not necessarily need a fast connection. The main advantage of a shared proxy is its low cost. Because they are shared by others, you may get blamed for someone else’s bad decisions, which could get you banned from a site.
SSL Proxy
A secure sockets layer (SSL) proxy provides decryption between the client and the server. As the data is encrypted in both directions, the proxy hides its existence from both the client and the server.
These proxies are best suited for organizations that need enhanced protection against threats that the SSL protocol reveals and stops. Because Google prefers servers that use SSL, an SSL proxy, when used in connection with a website, may help its search engine ranking. On the downside, content encrypted on an SSL proxy cannot be cached, so when visiting websites multiple times, you may experience slower performance than you would otherwise.
Rotating Proxy
A rotating proxy assigns a different IP address to each user that connects to it. As users connect, they are given an address that is unique from the device that connected before it.
Rotating proxies are ideal for users who need to do a lot of high-volume, continuous web scraping. They allow you to return to the same website again and again anonymously. However, you have to be careful when choosing rotating proxy services. Some of them contain public or shared proxies that could expose your data.
Reverse Proxy
Unlike a forward proxy, which sits in front of clients, a reverse proxy is positioned in front of web servers and forwards requests from a browser to the web servers. It works by intercepting requests from the user at the network edge of the web server. It then sends the requests to and receives replies from the origin server.
Reverse proxies are a strong option for popular websites that need to balance the load of many incoming requests. They can help an organization reduce bandwidth load because they act like another web server managing incoming requests. The downside is reverse proxies can potentially expose the HTTP server architecture if an attacker is able to penetrate it. This means network administrators may have to beef up or reposition their firewall if they are using a reverse proxy.
Proxy Server vs. VPN
On the surface, proxy servers and virtual private networks (VPNs) may seem interchangeable because they both route requests and responses through an external server. Both also allow you to access websites that would otherwise block the country you’re physically located in. However, VPNs provide better protection against hackers because they encrypt all traffic.
Choosing VPN or Proxy
If you need to constantly access the internet to send and receive data that should be encrypted or if your company has to reveal data you must hide from hackers and corporate spies, a VPN would be a better choice.
If an organization merely needs to allow its users to browse the internet anonymously, a proxy server may do the trick. This is the better solution if you simply want to know which websites team members are using or you want to make sure they have access to sites that block users from your country.
A VPN is better suited for business use because users usually need secure data transmission in both directions. Company information and personnel data can be very valuable in the wrong hands, and a VPN provides the encryption you need to keep it protected. For personal use where a breach would only affect you, a single user, a proxy server may be an adequate choice. You can also use both technologies simultaneously, particularly if you want to limit the websites that users within your network visit while also encrypting their communications.
How Fortinet Can Help
FortiGate has the capability of both proxies and VPNs. It shields users from data breaches that often happen with high-speed traffic and uses IPsec and SSL to enhance security. FortiGate also harnesses the power of the FortiASIC hardware accelerator to enhance performance without compromising privacy. Secure your network with FortiGate VPN and proxy capabilities. Contact us to learn more.
About proxy servers – IU KB
A proxy server, also known as a “proxy” or “application-level gateway”, is a computer that acts as a gateway between a local network (for example, all the computers at one company or in one building) and a larger-scale network such as the internet. Proxy servers provide increased performance and security. In some cases, they monitor employees’ use of outside resources.
A proxy server works by intercepting connections between sender and receiver. All incoming data enters through one port and is forwarded to the rest of the network via another port. By blocking direct access between two networks, proxy servers make it much more difficult for hackers to get internal addresses and details of a private network.
Some proxy servers are a group of applications or servers that block common internet services. For example, an HTTP proxy intercepts web access, and an SMTP proxy intercepts email. A proxy server uses a network addressing scheme to present one organization-wide IP address to the internet. The server funnels all user requests to the internet and returns responses to the appropriate users. In addition to restricting access from outside, this mechanism can prevent inside users from reaching specific internet resources (for example, certain websites). A proxy server can also be one of the components of a firewall.
Proxies may also cache web pages. Each time an internal user requests a URL from outside, a temporary copy is stored locally. The next time an internal user requests the same URL, the proxy can serve the local copy instead of retrieving the original across the network, improving performance.
Note:
Do not confuse a proxy server with a
NAT (Network Address Translation) device. A proxy server connects to, responds to, and receives traffic from the internet, acting on behalf of the client computer, while a NAT device transparently changes the origination address of traffic coming through it before passing it to the internet.
For those who understand the OSI (Open System Interconnection) model of networking, the technical difference between a proxy and a NAT is that the proxy server works on the transport layer (layer 4) or higher of the OSI model, whereas a NAT works on the network layer (layer 3).
This is document ahoo in the Knowledge Base.
Last modified on 2018-11-15 11:25:00.
Frequently Asked Questions about proxy server explained
What does a proxy server do?
A proxy server is a system or router that provides a gateway between users and the internet. Therefore, it helps prevent cyber attackers from entering a private network. It is a server, referred to as an “intermediary” because it goes between end-users and the web pages they visit online.
What is proxy server example?
Some proxy servers are a group of applications or servers that block common internet services. For example, an HTTP proxy intercepts web access, and an SMTP proxy intercepts email. A proxy server uses a network addressing scheme to present one organization-wide IP address to the internet.Nov 15, 2018
When would you use a proxy server?
Proxy servers can easily be used to increase speeds and save bandwidth on a network by compressing traffic, caching files and web pages accessed by multiple users, and stripping ads from websites. This frees up precious bandwidth on busy networks, so your team can access the internet quickly and easily.Jun 20, 2016
