Reverse proxy và forward proxy khác nhau thế nào? Tại sao reverse proxy quan trọng trong production?

Forward proxy đứng giữa client và internet: client cấu hình proxy, mọi request đi qua proxy — dùng để ẩn danh tính client, bypass geo-restriction, corporate filtering.

Reverse proxy đứng trước server: client không biết server thật sự, mọi request qua reverse proxy trước — dùng để load balancing, SSL termination, caching, compression, security (ẩn internal architecture). Reverse proxy quan trọng trong production vì:

1. SSL termination — giải mã HTTPS một lần tại proxy, backend dùng HTTP thuần
2. Load balancing giữa các server instances
3. Caching static assets, giảm load backend
4. Rate limiting và WAF protection
5. Gzip/Brotli compression. Nginx là reverse proxy phổ biến nhất; Caddy tự động HTTPS; Cloudflare là reverse proxy CDN toàn cầu. Trong Next.js/Vercel, Edge Network đóng vai trò reverse proxy trước Next.js server

A forward proxy sits between the client and the internet: the client is configured to route all requests through it — used to hide the client's identity, bypass geo-restrictions, or enforce corporate filtering.

A reverse proxy sits in front of servers: the client is unaware of the actual servers and all requests pass through the proxy first — used for load balancing, SSL termination, caching, compression, and security (hiding the internal architecture). Reverse proxies are critical in production because:

1. SSL termination — HTTPS is decrypted once at the proxy, so backends communicate over plain HTTP
2. load balancing across server instances
3. caching of static assets, reducing backend load
4. rate limiting and WAF protection
5. Gzip/Brotli compression. Nginx is the most popular reverse proxy; Caddy handles HTTPS automatically; Cloudflare acts as a global CDN reverse proxy. In Next.js/Vercel, the Edge Network acts as a reverse proxy in front of the Next.js server