Proxies

A proxy is an intermediary server that sits between a client and a server to facilitate communication, enforce security, or enhance performance. Depending on its position and purpose, a proxy can be categorized as:

1. Forward Proxy
2. Reverse Proxy

Forward Proxy

A forward proxy acts on behalf of the client. It is placed between the client and the internet. When the client makes a request, it goes through the forward proxy, which then forwards the request to the destination server.

Use Cases of Forward Proxy

1. Anonymity: Clients use forward proxies to hide their IP addresses.
2. Access Control: Organizations use forward proxies to restrict access to specific websites.
3. Caching: Forward proxies can cache responses to reduce latency and save bandwidth.
4. Content Filtering: Schools or workplaces use forward proxies to block certain types of content.

Reverse Proxy

A reverse proxy acts on behalf of the server. It is placed between the client and the server, and it intercepts client requests before they reach the actual server. The client may not even be aware of the reverse proxy's presence.

Use Cases of Reverse Proxy

1. Load Balancing: Distributes incoming requests across multiple servers.
2. SSL Termination: Handles SSL encryption and decryption, offloading this task from the servers.
3. Caching: Caches responses to improve performance and reduce the load on backend servers.
4. Security: Masks the identity of backend servers to protect them from direct attacks.
5. Compression: Compresses responses before sending them to the client.

Comparison Between Forward and Reverse Proxy

Feature	Forward Proxy	Reverse Proxy
Acts on behalf of	Client	Server
Primary purpose	Client anonymity, content filtering	Load balancing, security, performance
Typical user	Individuals, organizations	Websites, services
Placement	Between client and server	Between client and backend servers

Detailed Example

Forward Proxy Example

• A corporate network uses a forward proxy to block access to social media sites for its employees. When an employee tries to visit facebook.com, the request is intercepted by the proxy, which denies the request.

Reverse Proxy Example

• A website uses a reverse proxy to distribute traffic across multiple application servers. The client sends a request to www.example.com, and the reverse proxy forwards the request to one of the backend servers (app1.example.com, app2.example.com, etc.).