A cache and WAF in front of a web server
In brief
Puts a cache and a web application firewall in front of an existing site, on infrastructure you choose rather than a large CDN's. Its failure modes keep the site serving: a bad change is rolled back on the node, never taken live.
Declared sites are rendered into edge configuration by a control plane and applied by an agent on each node. The edge is nginx-lua with both WAF modules in front of go-proxy-cache and Redis, and Terraform lands the same shape on any of the five major providers.
What it does
- A node never takes itself out of service: a bundle that fails validation is restored and the node keeps serving
- One setting moves the whole WAF, rate limiting, bot scoring, geo rules and signatures, between off, log only and block
- A purge is a durable record queued per site, so a node that was rebooting applies it when it returns
A closer look
Select any screenshot to enlarge it.
The castellan.cloud landing page
The Castellan demo overview, signed in to an invented tenant
The sites and their WAF posture, in the Castellan demo
The whitepapers behind it
The problem it measures, the method behind it, and what it deliberately does not do.