What is a Proxy server in networking? | How does it work?

The word proxy means pretending to be something else than actual.  In some scenarios, the actual identity needs to be hidden for security and other reasons.  A proxy server in networking is a method for hiding client identity from the server.  On a daily basis you might be browsing sites, but never know how your information is captured by the network.   A company may grant you access via VPN only so that there will not be any exposure to confidential information. 

What is a Proxy server?

A proxy server is an intermediate machine that is located between the two communicating parties.  One side connects to the private network, such as a company’s LAN, and another side connects to the internet, which is a public network.

When you browse a website, the HTTP request from the web browser routes to the server over the public internet via proxy. The response comes via the same proxy server to your web browser.  Looks like it is a simple job, but in a real-world scenario, a proxy server adds many useful functionalities to a business or end-user.

How does a proxy server work?

Till now maybe you are not aware whether you have used any proxy server or not. As this is transparent for you.  To understand how it operates, let’s first understand what happens when you type a web address in the browser and hit the enter key? 

A request message goes to the server via the internet. On the internet, each machine has an IP address (maybe more than one).  An IP address is similar to a real-world postal address. When someone needs to send a post to you, the sender mentions your address on the envelope and posts via a post office.  May also mention his own address, so that if the courier guy can not deliver, you will get a return of the same.

Similarly, on the internet, a request has a destination IP address (webserver)  and source IP address (client or your machine).  The server processes the request and sends the response back to the client.  In this scenario, no proxy is involved

With a proxy, requests go to the proxy first. To make this happen, the proxy server works as a gateway and has its own IP address. The browser (or router in the office) knows, to forward the request to the proxy.   Then the proxy server initiates a new request with your data towards the webserver. Gets the response and forwards the same to you. So that you can see the response content.

Looks the same isn’t? So what the hell proxy server is doing?  The magic is in the way, it can modify the request and deliver the same response. A proxy can change the source IP address, so that server never knows about you.  It can block access to some websites or other resources. May use encryption before sending a request, to secure communication.

What are the advantages of a proxy server?

When using a middle man with great qualities and intelligence. It always adds value.  Companies providing proxies generally cover all use cases for a company or an Individual.   Depending on your need you can enable or disable a function.  Here we will cover the advantages mainly from a company’s point of view.  A company is always at a high risk of a security breach. So a good proxy can add many advantages to the operations.

Privacy –  The very basic advantage.  A company may choose to hide the identity of its employees and itself from some web servers.  Suppose a marketing company wants to get details from a server.  With a proxy, the server can not find who is requesting the information.

Content filtering –  A proxy server can parse the response from the server and it may stop content from going to the client.  It may be because content may have sensitive or unauthorized data.

Better Bandwidth Utilization –   The response may be cached by the proxy. So that if any other request comes, the same content can be delivered to the client without any request to the internet.  This looks simple, but it requires intelligence, as all responses can not be cached. e.g any live update of the cricket score can’t.

Restrict uploads –  An employee in a company may try to upload a local file to a personal server.  It may be direct FTP or an attachment in the mail.  The proxy can detect such kind of content and stop uploading the file to any public server.

Access to restricted resources –  Restrict resources means, you can not access an outer server from your computer.  This may be because of server has blocked the IPs you are using. But if you use a proxy, your actual IP will be hidden and you get access to resources.

Is Proxy use always good?

The answer is in the use case why do you need a proxy?   If yes, then go for a well-known proxy. The cheaper options may capture your information and will use for any other purpose.  Generally, a normal home user may not need a proxy at any time.  But maybe due to any virus attack from your computer, your IP has been blacklisted by some of the servers you were working on.  One option change an IP, or just use a proxy for time being until IPs are again whitelisted.