Nginx Rate Limiting — limit_req, limit_conn, and fail2ban
Tested on: Ubuntu 24.04 LTS, Nginx 1.26.x (nginx.org stable repository). All directives are core Nginx — no third-party modules required. Why this matters A web tier with no rate limiting fails in three predictable ways: Authentication brute force. A WordPress, application, or admin-panel login form with no rate cap is one credential-stuffing tool away from compromise. Signup / forgot-password abuse. Endpoints that send email, provision accounts, or issue tokens are expensive and attractive to spammers. Single-tenant noise becomes shared-tenant outage. One misbehaving client (or one bot) hammering an endpoint can starve FPM workers, application-server threads, and database connections. Rate limiting is not DDoS protection — that lives at the CDN / WAF layer if you need it. Nginx rate limiting is for the predictable, day-to-day class of behaviour: too many requests from too few sources to too few endpoints. Get this right and your origin survives even when something at the edge fails. ...