Proxy Server In Networking
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.
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.
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.
Types of Proxy Servers – eduCBA
Introduction to Proxy Servers
Proxy Servers are referred to those servers that act as an intermediary to the request made by clients to a particular server for some services or request for some resources. Several types of proxy servers are available whose use will depend on the purpose of a request made by the clients to the servers. The purpose of Proxy servers is to Protects the direct connect of Internet clients and internet and internet resources: Proxy server prevents the identification of the client’s IP address while any request is made to any other servers.
Internet clients and internal resources: Proxy servers also act as a shield for an internal network against the request coming from a client to access the data on that server. The original IP address of the node remains hidden while accessing data from that server.
Protects true host identity: Outgoing traffic appears to come from the proxy server. It must be configured to the specific application, e. g. HTTPS or FTP.
For example, as a client to MNC, a client can use a proxy to observe its contract employees’ traffic to get the work efficiently done. It can also be used to keep a check on any leakage of internal highly confidential data. Some can also use it to increase their websites rank and get the traffic diverted anonymously.
The need for Private Proxy
Some of the need for a private proxy is mentioned below:
Every organization has its own personal data that need to protect from malicious use. Thus, passwords are used, and different architects are set up, but there is still a possibility that this information can be hacked if the IP address is accessible easily. Proxy servers are set up to prevent tracking of the original IP address; instead, data is shown to come from a different IP address.
Filtering of the Content
Proxy servers also help filter out the content that doesn’t follow the web application’s policies or server required. It provides a facility to authenticate the user and provides the logs of URL of users requests made through that proxies.
Content can be Cached.
The proxy also helps in caching the content of the websites. This helps in fast access to the data that has been accessed oftenly.
Examine Packet Headers and Payloads
We can also examine the payloads and packet headers of the nodes in the internal server’s requests so that any access to social websites can be easily tracked and restricted.
Types of Proxy Servers
Below are the different types of proxy servers:
1. Reverse Proxy
This represents the server. In case there are multiple websites on different servers, then it is the job of a reverse proxy server to listen to the client’s request and redirect to the particular web server.
Example – Listen for TCP port 80 website connections. These are normally placed in a DMZ zone for publicly accessible services and protect the host’s true identity. It is transparent to the external users as external users will not be able to identify the actual number of internal servers. It is the duty of reverse proxy to redirect the flow depending on the configurations of internal servers. The request made to pass through the private network protected by firewalls needs a proxy server that does not abide by any local policies. This type of request from the clients are completed using reverse proxy servers. This is also used to restrict the client’s access to the sensitive data residing on the particular servers.
2. Web Proxy Server
This type of proxies forward the HTTP requests. This request is the same as HTTP requests; only URL is passed instead of a path. A request is sent to which the proxy server responds. Examples of such proxies are Apache, HAPProxy.
The client-server Proxy auto-config protocol solves the solution to the problems of multiple proxy servers.
3. Anonymous Proxy
This is the type of proxy server that does not makes an original IP address. Although these servers are detectable still provides rational anonymity to the client device.
4. High Anonymity Proxy
This proxy server does not allow the original IP address to be detected, and no one can detect it as a proxy server.
5. Transparent Proxy
This type of proxy server never provides any anonymity to the client; instead, an original IP address can be easily detected using this proxy. Still, it is being used to act as a cache for the websites.
A transparent proxy combined with gateway results in a proxy server where the client IP’s connection requests are redirected. This redirection occurs without the client IP address configuration. This redirection can be easily detected by the HTTP headers present on the server-side.
These are also known as intercepting proxies, inline proxy, and forged proxy.
Working: It intercepts the communication at the network level without the need for any configuration. It also works as a gateway or router that authenticates the communication without making any changes to the requests or responses passing through the server.
Uses: These types of proxies are most commonly used at the business level to enforce the policy over communication. It also tries to prevent any attack on TCP servers example – denial-of-service attack.
6. CGI Proxy
This type of proxies was developed to make the websites more accessible.
Working: It accepts the requests to target URLs using a web form, processes it and returns the result to the web browser. It is less popular due to VPNs and other privacy policies, but it still receives many requests these days. Its usage reduces because of excessive traffic that can be caused to the website after passing the local filtration, leading to collateral damage to the organization.
7. Suffix Proxy
This type of proxy server appends the proxy’s name to the URL to the content that has been requested to the proxy. This type of proxy doesn’t preserve a higher level of anonymity.
Uses: It is used for bypassing the web filters. This proxy is easy to use and can be easily implemented but is used less due to more or more web filters.
8. Distorting Proxy
Proxy servers can generate an incorrect original IP address of clients once being detected as a proxy server. It uses HTTP headers to maintain the confidentiality of the Client IP address.
9. TOR Onion Proxy
It is software that aims at online anonymity to the user’s personal information.
Working: It routes the traffic through various networks present worldwide to make it difficult to track the users’ address and prevent the attack of any anonymous activities. It makes it difficult for any person who is performing traffic analysis to track the original address. For this, it uses ONION ROUTING.
In this type of routing, the information is encrypted in a multi-folds layer by layer to prevent it. At the destination, each layer is decrypted to prevent the information from scrambling or getting distorted.
This software is open source as well as free of cost to use.
10. I2P Anonymous Proxy
It is an anonymous network enhanced version of the Tor onion proxy, which uses encryption to hide all the communications at various levels. This encrypted data is then relayed through various network routers present in different locations. Thus I2P is a fully distributed proxy that aims at online anonymity. It also implements garlic routing. (enhanced version of Tor’s pnion routing. It provides a proxy to all protocols. This type of proxies can be run on the node.
I2P router finds other peers to build an anonymous identity to protect the user’s personal information.
This software and network are free of cost and open source to use; It also resists censorship.
11. DNS Proxy
Unlike other proxies, this type of proxy takes requests in the form of DNS queries and forward them to the Domain server, where they can also be cached, and the flow of requests can also be redirected.
Types of Proxy Servers (Protocols)
Below are the different types of proxy servers protocols:
Socks Proxy Server: This type of proxy server provides a connection to a particular server. Depending on Socks protocols, this type of server allows the multilayering of various data types such as TCS or UDP.
FTP Proxy Server: This type of proxy server caches FTP requests’ traffic and uses the concept of relaying.
HTTP Proxy Server: This proxy was developed to process a one-way request to the web pages using HTTP protocols.
SSL Proxy Server: This type of server was developed using the concept of TCP relaying being used in the SOCKS proxy protocol to allow Web Pages’ requests.
Proxy servers help in various anonymity types required at different levels, either as a client or as a service provider. It helps to resist the security of information of various users as well as the internal network. Different types of proxies are available, which follow various routing protocols and serve different uses at different anonymity levels.
Proxifiers are the client programs that allow the adaptation of any type of software used for networking using various types of proxy servers.
This is a guide to Types of Proxy Servers. Here we discuss the basic concept, need, types and various protocols of Proxy Servers in detail. You can also go through our other suggested articles to learn more –
SOAP vs HTTP
What is TCP/IP?
Linux Proxy Server
Frequently Asked Questions about proxy server in networking
What is proxy with 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
What is proxy server and its types?
Proxy Servers are referred to those servers that act as an intermediary to the request made by clients to a particular server for some services or request for some resources. Several types of proxy servers are available whose use will depend on the purpose of a request made by the clients to the servers.
Where is a proxy server used?
Proxy servers are used for both legal and illegal purposes. In the enterprise, a proxy server is used to facilitate security, administrative control or caching services, among other purposes. In a personal computing context, proxy servers are used to enable user privacy and anonymous surfing.