In vB we were able to search on ranges of IP addresses, such as using only the first three octets (ie. 127.0.0.*). The search in XF appears to work only for full IP addresses, based on combinations I've tried ("127.0.0", "127.0.0.*", etc.). vB also had a "2-level" IP address search which was a bit more comprehensive. Our staff on the big board uses these to examine new members with suspicious activity--the forum tends to attract trolls, and they like to see if there is any history of other suspicious members that were banned.