1. A method of scanning data in a computer network, the method comprising: scanning data against a knowledge base of a first computer; forwarding the data from the first computer to a second computer over a computer network after the data has been scanned against the knowledge base of the first computer; and scanning the data against a knowledge base of the second computer, the scanning of the data against the knowledge base of the second computer being performed based on the scanning of the data against the knowledge base of the first computer.