What is a Proxy Server?
At its core, a proxy server is a middleman between a client (which could be a user or a device) and a server. It serves several key functions:
Privacy and Anonymity: A proxy server hides the client's IP address from the outside world, offering a layer of anonymity.
Access Control: It can restrict or grant access to specific content or websites, bolstering security measures.
Content Caching: Proxy servers can cache frequently accessed content, reducing load times and conserving bandwidth.
Geolocation Bypass: Users can access content that might be geographically restricted or blocked in their region.
Load Balancing: In some instances, proxies can distribute incoming requests among multiple servers for load balancing, ensuring optimal resource usage.
Forward Proxy
A forward proxy operates at the application layer and requires configuration for each application. It acts on behalf of the client, providing anonymity, grouping requests, enabling access to blocked content, enhancing security, and even caching content for faster access. Some widely used forward proxy technologies include Squid Proxy, Apache HTTP Server with mod_proxy, and Nginx with its proxy module.
Reverse Proxy
Conversely, a reverse proxy acts on behalf of the server. It brings added security, capable of handling Distributed Denial of Service (DDoS) attacks, caching server responses, and even load balancing client requests. Content Delivery Networks (CDNs) are essentially reverse proxies. Popular reverse proxy solutions are Nginx, HAProxy, and Apache HTTP Server with mod_proxy.
Proxy vs. VPN
While both proxies and Virtual Private Networks (VPNs) enhance privacy, they differ significantly:
VPN (Virtual Private Network): It creates an encrypted tunnel for all network traffic, providing comprehensive privacy and security. Examples of VPN technologies include OpenVPN, Cisco AnyConnect, and NordVPN.
Proxy: A proxy can mask the client's IP address but doesn't encrypt data. Common proxy services include SOCKS proxies, HTTP proxies, and residential proxies.
Reverse Proxy vs. Load Balancer
Here's how reverse proxies and load balancers differ:
Reverse Proxy: It acts as a gateway for client requests to reach backend servers, often providing security and caching features. An example is Nginx acting as a reverse proxy.
Load Balancer: Load balancers primarily focus on distributing incoming requests among multiple backend servers to achieve load balancing. AWS Elastic Load Balancing and HAProxy are examples of load balancers.
Proxy vs. Firewall
Proxy servers and firewalls have distinct roles:
Proxy: Operates at the application layer, capable of controlling and inspecting application-level traffic.
Firewall: Works at the network layer, typically performing packet inspection and filtering. Examples include Cisco ASA and pfSense.
Sources : https://www.upguard.com/blog/reverse-proxy-vs-load-balancer