A dial-up-list (DUL) is simply a list of network ranges that is assigned to dial-up users. In a previous post I discussed building such a DUL purely from whois information. This turned out to be a horrific failure as there is no common, usable, standard with regards to the information in the information returned by whois.
Whilst browsing the mail logs looking for where the newest spam flood was coming from another idea presented itself …
