LLM bots make only a part of traffic and really easy to set up (and I think this will eventually throttled by OAI or Anthropic themselves).
But there are bad actors - bots that try every possible urls and traversals and cross scripting and so on… I see it in our access logs. This cannot be solved otherwise than some greylisting/blacklisting on ISP level. E.g. this is so huge that we have started to block all Chinese inbound traffic. I am sorry for that because Deepseek and other good actors are probably blocked as well but IP rotation made it impossible to filter bad ones only… (and I suppose that DS uses EU or US addresses as well so they shouldn’t be blocked in full).
eventually throttled by OAI or Anthropic themselves
Indeed, they use an edge SSL Bump proxy that is already bandwidth limited and has to speak real HTTPS.
I do not focus too much on IP addresses but rather the behavior that they can not hide. LLM's can help you spot this behavior. Good LLM vs. Bad LLM. Gemini knows a few tricks but you have to coax it out of them. It seems to not want to overload people with information. That said there are some good IP lists that can be used in blackhole routing tables, nginx geo tables, etc...