What did you have in mind as far as a use case?
(for fraud detection it switches from block to identify)
for IPv4 this is generally the /32 (the single IPv4 address)
for IPv6 it's probably a /64, but may be a /56 or even a /48, and on some crappy providers even a /128
if the subnet is smaller than you think it is you risk banning an entire ISP (or country), whereas if if it's too large the abuse continues
it's quite a complicated problem as by design you can have subletting (subnetting!) within a block, e.g. a VPS provider gets a /48 from its ISP, and then they sublets out /64s to their customers (while not necessarily giving them all their own RIPE/ARIN records)
The other aspect is that a decent chunk of the IPv4 space at least is fairly dynamic. We've seen some blocks change owners every few weeks.
if i spent like a hundred bucks or something, i dont know... just asking. how would that work, does that "bring your own ip" that vps providers talk about mean this?
i
In pactice you cannot have less than a /24 because nobody will announce less than a /24
Edit: Seeing your use-case, this should probably be part of the whois records.
absolutely, assuming people subnetting to their customers delegate the space in the whois accordingly
(they do have an incentive to do that -- prevents all of their customers being banned if one misbehaves!)
would be very useful
(business opportunity here guys!)