Symantec 10521146 Administration Guide - Page 354

354 Glossary packet filter A filter that keeps out certain data packets based on their source and destination addresses and service types. You can use packet filters to block connections from or to specific hosts, networks, or ports. Packet filters are simple and fast, but they make decisions based on a very limited amount of information. packet filtering A firewall technique that examines the headers of packets requesting connection to a computer behind the firewall and either grants or denies permission to connect based on information held within the packet header according to a set of preestablished rules. packet sniffing The interception of packets of information (for example, a credit card number) that are traveling across a network. PAD See Protocol Anomaly Detection. PAP (Password Authentication Protocol) A procedure used to validate a connection request. After the link is established, the requester sends a password and an ID to the server. The server either validates the request and sends back an acknowledgement, terminates the connection, or offers the requester another chance. parallel port A port that transmits synchronous, high-speed flow of data along parallel lines. Parallel ports are usually used for printers. parameter A value that is assigned to a variable. In communications, a parameter is a means of customizing program (software) and hardware operation. passphrase A unique string of characters that a user types as an identification code to restrict access to computers and sensitive files. The system compares the code against a stored list of authorized passwords and users. If the code is legitimate, the system allows access at the security level approved for the owner of the password. password-based attack An attack in which repetitive attempts are made to duplicate a valid logon or password sequence. patch A type of programming code that is used to repair an identified software bug or vulnerability or mitigates a vulnerability by resolving the underlying implementation error. payload The part of the packet, message, or code that carries the data. In information security, payload generally refers to the part of malicious code that performs the destructive operation. permissions A set of rights of a user determining the level of access to Symantec Network Security components and functions. Permissions are granted through assignment of predefined accounts to Users. See user account. PGP (Pretty Good Privacy) A freeware (for non-commercial users) encryption program that uses the public key approach: messages are encrypted using the publicly available key, but the intended recipient can only decipher them via the private key. PGP is perhaps the most widely used encryption program.