What is a web proxy server?

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What is a web proxy server?

A web proxy server is a computer situated between your PC and a website server you are requesting a data/webpage from. There are two common reasons for using a web proxy:

  1. To speed up browsing by caching webpage data (a Web cache or CDN) therefore saving a full trip and download from the website you are visiting.
  2. To stay anonymous towards the website you are visiting whereby the web proxy acts as a “go between”. The website server will only see and/or log the proxy IP address, not your machines IP address.

The visual diagram 1.a below shows how and where a proxy is located on the network chain with further explanation below.

Diagram showing the network flow of a web proxy server, also known as a caching server.

Web Proxy Server

  1. Computer number #1 is your home machine. Its IP address is 127.158.84.110. Lets say you open your web browser and enter the website address www.example.com. Your computer will send a request for www.example.com but because you are using a proxy server, that request will be sent to the proxy server first, not the www.example.com web server.
  2. Computer number #2 is the proxy server. Its IP address is 167.101.22.126. The proxy server receives the request from your home computer for www.example.com. It then sends the same request to the www.example.com web server, but uses its own IP address of 167.101.22.126, not your home computers IP address.
  3. Computer number #3 is the web server that hosts www.example.com. It receives the request from the proxy server, and logs its IP address of 167.101.22.126. It then sends the web page back to the proxy server, then the proxy server sends it back to your home computer, completing the entire transfer request.

Caching Proxy Server

Number #4 in our diagram is the proxy server cache. When the Proxy receives the webpage from www.example.com it stores a local copy of it (html, images etc.) on it’s hard drive along with a time-stamp. Lets say 30 minutes later you decide to visit www.example.com again and your request is sent to the proxy server, but this time the proxy simply checks if the page on the web server has been altered in the past 30 minutes by comparing the time-stamp it recorded, with the last modified date and time of the web page. If the web page has not changed in the past 30 minutes, the proxy server will send the cached local copy of www.example.com web page, making the entire process much faster than downloading the entire page and data again.

The caching example above is one of many ways a proxy decides when to send the cached copy of a web page, and when to retrieve a fresh version, it really depends on the software used and it’s settings.

Summary

Hopefully this article has informed you all about proxy servers and what they’re used for. If you have any questions, hit me up in the comments or social/email.

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Categories Firewalls & Security

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