NGINX Abuse Guard Module Blocks Scanners and Bots in Real Time Inside the Worker

A new NGINX module called Abuse Guard automatically bans clients that generate excessive error responses, such as repeated 404s or 403s typical of vulnerability scanners and credential-stuffing bots. Unlike tools such as fail2ban, which parse logs externally with a delay, Abuse Guard operates entirely inside the NGINX worker process, making ban decisions in microseconds using compiled C code. The module tracks a per-client error score in shared memory, incrementing it on each matching bad response and draining it gradually over time, so brief bursts trigger bans while occasional stray errors do not. Bans are enforced at the preaccess phase, meaning NGINX turns away offending clients before routing, file lookups, or upstream proxying even begin. Banned clients receive a 429 Too Many Requests response with a Retry-After header, and no sidecar process, log shipper, or external firewall rule is required.