isabelle-dev.sketis.net and isabelle.sketis.net down for maintenance

[Makarius]

There have been a couple of private notes, hints, and recommendations. This is 
my current understanding of possible approaches:

   (1) Block particular User-agent names from the other side, e.g. this list
https://github.com/ai-robots-txt/ai.robots.txt/blob/main/robots.txt --- not 
via robots.txt (which is often ignored), but hardwired into the Webserver.

   Weakness: AI bots often don't identify themselves properly.

   (2) Block particular address ranges, e.g. according to this list 
https://github.com/JasonLovesDoggo/caddy-defender/blob/main/ranges/data/generated.go

   Weakness: this is neither correct nor complete, i.e. legitimate users could 
use a cloud address, bad addresses could be missing. Maybe it is better not to 
block completely, but to reduce the bandwidth for such addresses.

   (3) Aggressive counterstrikes, e.g. via proof-of-work imposed on the other 
side, e.g. see https://anubis.techaro.lol

   Weakness: answering war by more war is not a winning strategy.


	Makarius