Think of it as defense-in-depth. This allows higher-level, but more sophisticated rules, while your lower layers provide simpler but lower overhead filtering. H

Think of it as defense-in-depth. This allows higher-level, but more sophisticated rules, while your lower layers provide simpler but lower overhead filtering. Hopefully abusive requests never reach this thanks to your router / firewall / web server rules, but if they do, this will help keep things in check.