Methods and apparatus for computer network security using intrusion detection and prevention

A method for providing security to a computer network by selectively blocking network transmissions from selected IP addresses comprising the steps of:

• establishing a risk threshold whereby transmissions from IP addresses exceeding said risk threshold are selectively blocked;
• receiving a network transmission having an originating IP address and payload;
• analyzing the payload of said transmission and assigning a current risk rating to said IP address on the basis of said analysis;
• comparing the originating IP address of said transmission to a database of known IP addresses, each of said known IP addresses having a previous cumulative assigned risk rating, said previous cumulative assigned risk rating being based on at least one previous transmission from a known IP address;
• if the originating IP address is in the database of known IP addresses, then assigning a new cumulative risk rating to said originating IP address, said new cumulative risk rating being the sum of said current risk rating and said previous cumulative assigned risk rating for said originating IP address, otherwise, said new cumulative risk rating is set to equal said current risk rating;
• logging the new cumulative risk rating for said originating IP address in said database of known IP addresses, with the proviso that where said originating IP address of said transmission is not contained in said database of known IP addresses, a new record is created for said originating IP address and said new cumulative risk rating in said database of known IP addresses;
• comparing said new cumulative risk rating to said risk threshold;
• and
• automatically blocking said transmission if said new cumulative risk rating exceeds said risk threshold.