Forward Proxy and Reverse Proxy

Communication between servers works so seamlessly these days that it is often easy to overlook the many intermediary systems that exist in between, namely forward proxies and reverse proxies.

A forward proxy is a layer between a group of client machines, often within the same network, and the rest of the Internet. Traffic going out to the Internet will pass through this forward proxy first. In other words, the forward proxy acts as a middleman who intercepts the outgoing requests and forwards them to the destination server on the client’s behalf. A forward proxy has the benefits of protecting the clients’ IPs, bypassing browsing restrictions established by institutions and governments, and can block access to certain resources with filtering rules.

A reverse proxy is a layer between a group of servers and the Internet. Similarly, the servers and the reverse proxy are often within the same network. All incoming traffic bound to the server must pass through the reverse proxy first. The reverse proxy also provides the benefits of protecting the servers’ IPs, acts as a load balancer that distributes traffic amongst the servers, caches static content, and handles TLS/SSL handshakes.

It is not uncommon for both forward proxies and reverse proxies to be used at the same time. Also, there could be multiple layers of reverse proxies between the Internet and the servers.