As sad as it makes me, blocking large parts of the world that you don't expect to connect from via a list of CIDR blocks is an incredibly effective way to secure anything and reduce logspam.
I personally use nft blackhole [1], which I can recommend for its ease of use.
I personally use nft blackhole [1], which I can recommend for its ease of use.
[1] https://github.com/tomasz-c/nft-blackhole