Abstract: A method and system that identifies connection attempts to a resource through the IP address used in the connection and compares the IP address against one or more of single or multiple lists of IP addresses simultaneously to affect the connection process. The result of the comparison against the list is used to either block or allow access to the resource or to perform some other action based on the presence of the connecting IP Address on said list(s). The lists are retrieved in native format from one or more sources and compiled into a format allowing high speed comparisons or lookups against the list. The lists may be blacklists containing known addresses that have performed offensive actions or whitelists containing known safe or vetted IP addresses, or other lists used to determine the course of intended action.