proxy-addr smartly determines the address of the client connecting to your Node.js server through a reverse proxy. It analyzes the X-Forwarded-For and related headers, taking into account trusted proxies you configure. The package offers configurable trust settings, supporting IP addresses, CIDR notations, and functions for custom trust evaluation. This helps accurately identify the client's IP, crucial for tasks like rate limiting, security, and geolocation, even behind complex proxy setups.