This is my effort to share my experiment and notes about web proxies with you.
Simply defined, proxies/servers are the application (or dedicated server) that enables the indirect connection between a client and a resource on a remote location. Initially, proxies were invented to provide many functions such as server load balancer, fast delivery of contains to support a distributed system but later more functionality such as encryption, traffic filtering, redirection, URL rewrite and deep packet inspection was added.
Type of proxies
Although there are many type of proxies such as Web proxy, FTP, SOCKs and more, in this document is focused on Web proxy.
Web Proxy
The most popular proxies over the internet are Web proxies those were built
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o All other traffic that is initiated by another source, such as curl, wget, API's, ftp clients or from a different browser (without explicit proxy), will be forward to machines default gateway.
• How to configure explicit proxy? o Direct configuration:
One can manually set a browser's network setting for proxy by providing the Destination IP(DIP) and Destination Port(DPort) and supported protocols.
In this case all traffic is forwarded to the proxy; however, there is another way in where traffic is forward to proxy based on requested URL. o Proxy Auto Configuration (PAC file) and its location in network in form of URL:
• A PAC file is a text file of functions and the URLs to reroute the traffic based on URLs. For example, in an enterprise setting, a PAC file can define the rules such as if the URL (or end-point) is an external address then next hop is another proxy and if end-point is internal address then send it directly to the destination.
• A PAC file resides on a server, and a browser will access the PAC file using a given URL.
• The PAC file should be on the root of the severing server
• For configuration, select browser-> network settings-> auto configuration-> use auto configuration script-> and give location “ Error! Hyperlink reference not valid. address of server:port/proxy.pac”
• A PAC file may looks as following: function FindProxyForURL(url, host)
{ if (!shExpMatch(url,
But how does it work? The internet, based on the concept of “packet switching”, involves the travelling of small packets of data over one or more networks (Frenzel, 2013). This can be compared to “electronic postcards”, meaning that “a computer generates a piece of data and flings it into the net, just like the postal system, except 100 million times faster” (Cerf, 2013). This concept allows one computer to speak to many different computers around the network by sending out these “electronic postcards”. However, before these networks can work seamlessly together, they must use a common protocol, or set of rules for transmitting and receiving these packets of data. There are several protocols currently in use, including the OSI Model, the TCP/IP Model, UDP, HTTP, and FDP (Mitchell, 2014), but the most commonly used is Transmission Control Protocol/Internet Protocol (TCP/IP) (Gilmer, 2011). Even as early as 1977, TCP/IP was being used by other networks to link to ARPANET (Kozierok,
Domain structure – the Domain Structures allows the users or the program to interpret different information. For example take the address: http://www.netflix.com/
When you type in a web address, e.g.www.google.com. DNS associates with the domain name, translates into IP address (for example 192.168.154.70 is the IP for google.com) and directs your Internet connection to the correct website.
DNS (Domain Name System) : used to translate the internet protocol services. Stand-alone daemon run by script named.
The alternate domain name (CNAME) is the place where you’ll put the URL to pull the content from.
In this document you will learn how to use the alternative ways to search the Internet anonymously using Tor and proxy servers.
Web servers use port number ___ by default and the default port number for an SSL connection is ___ .
Proxy – Forward and reverse proxy features secure published applications in Internet-facing deployments, in part by providing network separation between remote clients and internal network servers. TMG’s forward proxy capabilities include content filtering to provide more control over access to public content and to manage SSL- based traffic. TMG as a reverse proxy is deployed in front of the Web and application servers to process client requests for content and support application firewall and other security techniques.
12. Which Web page appears when you key a URL containing the server’s IP address instead of a name? Why?
In this section, important functions used to send and get requests to and from the traffic
VPN refers to the networking technology Virtual Private Network. A VPN allows users connected to this network the ability to access any website or computer data from any location in the world with dedicated and secure networking environment rather than being present in a public server. Majority of VPN users belong to business class industry and educational purposes. VPN networks are used in this manner because majority of VPN networks offer the features like encryption and anonymity which increases the privacy and security benefits while using the VPN network. VPN networks also allow the user ability to perform activities on the internet as if they were accessing
Several websites allow you to use a proxy server through a web browser and bypass your ISP . This is used to hide your IP address as all your internet requests will go through the proxy server so your ISP doesn’t know it was you who sent it.
The Internet is, quite literally, a network of networks. It is comprised of ten thousands of interconnected networks spanning the globe. The computers that form the Internet range from huge mainframes in research establishments to modest PCs in people's homes and offices. Despite the recent hype, the Internet is not a new phenomenon. Its roots lie in a collection of computers that were linked together in the 1970s to form the US Department of Defense's communications systems. Fearing the consequences of nuclear attack, there was no central computer holding vast amounts of data, rather the information was dispersed across thousands of machines. A set of rules, of protocols, known as TCP/IP was
Computers (and other network devices like smartphones or tablets) use IP addresses to identify each other on the network and route your request to the site you are trying to access. It is just like dialing a phone number to reach the person you want to talk to, but thanks to DNS, you don’t need to maintain your own address book of IP addresses. You will simply connect via DNS server (also called “domain name server” or just “name server”). Domain name system servers match domain names like coursera.org to their associated IP addresses.
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite (TCP/IP) to serve billions of users worldwide. It is a network of networks that consists of millions of private, public, academic, business, and government networks, of local to global scope, that are linked by a broad array of electronic, wireless and optical networking technologies. The Internet carries a vast range of information resources and services, such as the inter-linked hypertext documents of the World Wide Web (WWW) and the infrastructure to support electronic mail.