Where did you find about publisher throughput of 700 req/sec ? Is it documented in Adobe documentation?  -- On my own load testing for publish on 404 scenario. Not documented in Adobe documentation. Please note that you can do vertical/horizontal scaling to increase throughput. If you are on AEMaaCS...

   Continuously scan your publisher logs, to find common 404 patterns and add these patterns to the dispatcher's farm filter or CDN.      -- this won't work for us since the pattern change every time.      Configure DDoS Protection [4] on CDN, this will block any attempt of attack on the server.    ...

I know page should be cached in dispatcher and cdn.  I'm worrying some malicious site scan requests may cause publish  cpu exhaustion.

I  can setup 404 page at dispatcher/apache level, but AEM publish have to return 404 response code before apache can handle it.

I had ran a load test for 404 response on a 8 core 16GB AEM publish instance.  The request urls are something like https://www.myhost.com/content/abc/${__Random(1,1000000)}/,and the response is set in /apps/sling/servlet/errorhandler/404.jsp: <% response.setStatus(404); response.setContentTy...