White hat (computer security) White hat (computer security) The term "white hat" in Internet slang refers to an ethical computer hacker, or a computer security expert, who specializes in penetration testing and in other testing methodologies that ensures the security of an organization's information systems. Ethical hacking is a term meant to imply a broader category than just penetration testing. Contrasted with black hat, a malicious hacker, the name comes from Western films, where heroic and antagonistic cowboys might traditionally wear a white and a black hat respectively. While a white hat hacker hacks under good intentions with permission, and a black hat hacker
Longest prefix match Longest prefix match Longest prefix match (also called Maximum prefix length match) refers to an algorithm used by routers in Internet Protocol (IP) networking to select an entry from a forwarding table. Because each entry in a forwarding table may specify a sub-network, one destination address may match more than one forwarding table entry. The most specific of the matching table entries — the one with the longest subnet mask — is called the longest prefix match. It is called this because it is also the entry where the largest number of leading address bits of the destination address match