I have a lot of login attempts from China, Taiwan, Korea, Russia etc. always following the pattern Username: art, art@domain.tld, arts, arts@domain.tld. In a short time, there are always a lot of requests with completely different IP addresses but all from the countries mentioned. Now I have come up with the idea of blocking something like this with geoip-shell. My machine has Debian 12 as OS and only Mailcow runs on it. Is this a good idea or do you have another suggestion?