the simplest way is to do domain searches for registered ranges- yesterday i had luck doing wildcard searches on arin (eg- baytsp* ) and was surprised to find a bunch that weren't on the recommended list- there are also sophisticated methods that take more time... the problem right now us ppl think they're detectives or something- they get port scanned by someone and then they get the range which could be huge- an isp or a school and then add it to the database which is plain stupid- ppl are forgetting it's an anti p2p database... automatic port scans happen all the time