Types of Proxies

Proxies can sit on the client’s local server side and also somewhere between the client and remote servers which we are going to discuss. Basically, they are of 2 types only because the proxy server can reside on the client’s local server or anywhere between the client and the remote servers.

1. Forward Proxy

An open proxy is a proxy server that is accessible by any Internet user. Generally, a proxy server only allows users within a networking group (i.e. a closed proxy) to store and forward Internet services such as DNS or web pages to reduce and control the bandwidth used by the group. With an open proxy, however, any user on the Internet is able to use this forwarding service.

When to use a forward proxy server?

• Forward proxies are in handy when we don’t want the main server to be able to see the client’s IP because it only has the proxy server’s IP.
• Used in scenarios where a large number of clients are present and the proxy server is handling all traffic.
• Used when we block a specific website.
• Putting forward proxy sites in the response’s cache.

Note: Forward proxy is also known as ‘Open Proxy’.

2. Reverse Proxy

A reverse proxy retrieves resources on behalf of a client from one or more servers. These resources are then returned to the client, appearing as if they originated from the proxy server itself. It typically sits behind the firewall in a private network and directs client requests to the appropriate backend server. A reverse proxy provides an additional level of abstraction and control to ensure the smooth flow of network traffic between clients and servers.

When to use a reverse proxy server?   

• Management of traffic control.
• Load balancing: Distributes client requests in a certain manner across servers ensuring no server is overloaded leading to higher speed and capacity utilization. If any server goes down the load balancer redirects to other servers available.  
• Reducing DDoS attacks. It is because only proxy server is accessible to the outer world where servers are not. 
• Caching a server response. 
• SSL encryption reduces the strain on the web server and improves client-server architecture performance.

Note: Reverse proxy is also known as ‘Closed Proxy’.

In system design, web servers and proxies play crucial roles in ensuring efficient communication and scalability. Web servers, like Apache or Nginx, serve as the backbone of client-server interactions, handling requests and delivering content. Proxies act as intermediaries, managing traffic flow, improving performance, and enhancing security by caching and load balancing. Together, they form the core infrastructure of distributed systems. Understanding their roles and integration is fundamental for designing resilient and high-performing systems.