Chapter 4. NGINX as a Reverse Proxy

A reverse proxy is a web server that terminates connections with clients and makes new ones to upstream servers on their behalf. An upstream server is defined as a server that NGINX makes a connection with in order to fulfill the client's request. These upstream servers can take various forms, and NGINX can be configured differently to handle each of them.

NGINX configuration, which you have been learning about in detail, can be difficult to understand at times. There are different directives that may be used to fulfill similar configuration needs. Some of these options should not really be used, as they can lead to unexpected results.

At times, an upstream server may not be able to fulfill a request. NGINX has the capability to deliver an error message to the client, either directly from this upstream server, from its local disk, or as a redirect to a page on a completely different server.

Due to the nature of a reverse proxy, the upstream...