Figure 2
From: Neighborhoods and bands: an analysis of the origins of spam
Distribution of active IP numbers per AS, as well as the distribution of the number of IPs from an AS present in the XBL, PBL black lists (or not present in any BL).(a) CDF of the number of IP addresses per AS. (b) CDF of the percentage of IP addresses in XBL per AS. (c) CDF of the percentage of IP addresses in PBL per AS. (d) CDF of the percentage of IP addresses that are not in any blacklist per AS.