EEye Digital Security Retina User Manual page 91

Glossary
D
Daisy Chain: A local networking topology in which a single cable runs to multiple workstations. This tends to be less
expensive than the alternative "star" topology, but it is also less robust. A break anywhere along the "chain" disables
the entire chain. Daisy chains are most often used in PhoneNet or thinnet cabling.
DARPA: Defense Advanced Research Projects Agency. This is an agency of the U.S. Department of Defense
responsible for the development of new technology for use by the military. DARPA (formerly known as ARPA) was
responsible for funding much of the development of the Internet we know today, including the Berkeley version of Unix
and TCP/IP.
Data Encryption Standard (DES): DES is a popular standard encryption scheme. Developed by IBM in the 1970's,
DES uses a 56-bit encryption key and was originally designed to run in hardware.
Datagram: A self-contained, independent entity of data carrying sufficient information to be routed from the source to
the destination computer without reliance on earlier exchanges between this source and destination computer and the
transporting network.
Default Route: A routing table entry that is used to direct packets addressed to networks not explicitly listed in the
routing table.
DES: See: Data Encryption Standard
Dialup: A temporary, as opposed to dedicated, connection between machines established over a standard phone
line.
Distributed Database: A collection of several different data repositories that looks like a single database to the user.
A prime example in the Internet is the Domain Name System.
DNS: See Domain Name System
Domain Name System (DNS): The DNS is a general purpose distributed, replicated, data query service. The
principal use is the lookup of host IP addresses based on host names. The style of host names now used in the
Internet is called "domain name" because they are the style of names used to look up anything in the DNS. Some
important domains are:
COM (commercial)
EDU (educational)
NET (network operations)
GOV (U.S. government)
MIL (U.S. military)
Most countries also have a domain such as, .US (United States), .UK (United Kingdom), .AU (Australia), and so on. It
is defined in std 13, RFCs 1034 and 1035. See also: Fully Qualified Domain Name.
Domain: A part of a naming hierarchy in the Internet. Syntactically, an Internet domain name consists of a sequence
of names (labels) separated by periods (dots).
DoS (Denial of Service): A DoS attack is a remote attack against a servers TCP/IP stack or services. DoS attacks
can saturate a server's bandwidth, saturate all available connections for a particular service, or even crash a server.
Dot Address (dotted decimal notation): Dot address refers to the common notation for IP addresses of the form
A.B.C.D, where each letter represents, in decimal, one byte of a four-byte IP address.
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