ZyXEL P-964 User Guide - Page 44

P964 APR Cable Sharing Gateway with 4-port Switch Cracker Tools Cracking Crossover Ethernet cable Cryptoanalysis CSU/DSU DCE Decryption Denial of Service DHCP Digital Signature Programs used to break into computers. Cracker tools are widely distributed on the Internet. They include password crackers, Trojans, viruses, war-dialers, and worms. The act of breaking into computers or cracking encryptions. A cable that wires a pin to its opposite pin, for example, RX+ is wired to TX+. This cable connects two similar devices, for example, two data terminal equipment (DTE) or data communications equipment (DCE) devices. The act of analyzing (or breaking into) secure documents or systems that are protected with encryption. Channel Service Unit/Data Service Unit. CSUs (channel service units) and DSUs (data service units) are actually two separate devices, but they are used in conjunction and often combined into the same box. The devices are part of the hardware you need to connect computer equipment to digital transmission lines. The Channel Service Unit device connects with the digital communication line and provides a termination for the digital signal. The Data Service Unit device, sometimes called a digital service unit, is the hardware component you need to transmit digital data over the hardware channel. The device converts signals from bridges, routers, and multiplexors into the bipolar digital signals used by the digital lines. Multiplexors mix voice signals and data on the same line. Data Communications Equipment is typically a modem or other type of communication device. The DCE sits between the DTE (data terminal equipment) and a transmission circuit such as a phone line. The act of restoring an encrypted file to its original state. Act of preventing customers, users, clients or other machines from accessing data on a computer. This is usually accomplished by interrupting or overwhelming the computer with bad or excessive information requests. Dynamic Host Configuration Protocol automatically assigns IP addresses to clients when they log on. DHCP centralizes IP address management on central computers that run the DHCP server program. DHCP leases addresses for a period of time which means that addresses are made available to assign to other systems. Digital code that authenticates whomever signed the document or software. Software, messages, Email, and other electronic documents can be signed electronically so that they cannot be altered by anyone else. If someone alters a signed document, the signature is no longer valid. Digital signatures are created when someone generates a hash from a message, then encrypts and sends both the hash and the message to the intended recipient. The recipient decrypts the hash and original message, makes a new hash on the message itself, and compares the new hash with the old one. If the hashes are the same, the recipient knows that the message has not been changed. Also see Public-key encryption. DNS DOCSIS Domain Name Downstream Downstream Frequency DRAM DTE EMI Encryption Ethernet Events FAQ Domain Name System. A database of domain names and their IP addresses. DNS is the primary naming system for many distributed networks, including the Internet. Data over Cable Service Interface Specification. It is the dominating cable modem standard, which defines technical specifications for both cable modem and CMTS. The unique name that identifies an Internet site. Domain Names always have 2 or more parts, separated by dots. The part on the left is the most specific, and the part on the right is the most general. The data flowing from the CMTS to the cable modem. The frequency used for transmitting data from the CMTS to the cable modem. Normally in the 42/65-850 MHz range depending on the actual cable plant capabilities. Dynamic RAM that stores information in capacitors that must be refreshed periodically. Originally, the DTE (data terminal equipment) meant a dumb terminal or printer, but today it is a computer, or a bridge or router that interconnects local area networks. ElectroMagnetic Interference. The interference by electromagnetic signals that can cause reduced data integrity and increased error rates on transmission channels. The act of substituting numbers and characters in a file so that the file is unreadable until it is decrypted. Encryption is usually done using a mathematical formula that determines how the file is decrypted. A very common method of networking computers in a LAN. There are a number of adaptations to the IEEE 802.3 Ethernet standard, including adaptations with data rates of 10 Mbits/sec and 100 Mbits/sec over coaxial cable, twisted-pair cable, and fiber-optic cable. The latest version of Ethernet, Gigabit Ethernet, has a data rate of 1 Gbit/sec. These are network activities. Some activities are direct attacks on your system, while others might be depending on the circumstances. Therefore, any activity, regardless of severity is called an event. An event may or may not be a direct attack on your system. (Frequently Asked Questions) -- FAQs are documents that list and answer the most common questions on a particular subject. F Glossary