Symantec 10521146 - Network Security 7120, Руководство администратора

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344 Glossary
digital certificate A digital certificate is an electronic credit card that establishes a user's credentials when
doing business or other transactions on the Web. It is issued by a Certificate Authority
(CA). It contains the user's name, a serial number, expiration dates, a copy of the
certificate holder's public key (used for encrypting and decrypting messages and digital
signatures), and the digital signature of the certificate-issuing authority so that a
recipient can verify that the certificate is real.
digital signature An electronic rather than a written signature that can be used by someone to authenticate
the identity of the sender of a message or of the signer of a document. It can also be used
to ensure that the original content of the message or document that has been conveyed is
unchanged. Additional benefits to the use of a digital signature are that it is easily
transportable, cannot be easily repudiated, cannot be imitated by someone else, and can
be automatically time-stamped.
direct connection A form of data communication in which one computer is directly connected to another,
usually via a null modem cable.
disabled A status that indicates that a program, job, policy, or scan is not available. For example, if
scheduled scans are disabled, a scheduled scan does not execute when the date and time
specified for the scan is reached.
DMZ (de-militarized
zone) A network added between a protected network and an external network to provide an
additional layer of security. Sometimes called a perimeter network.
DNS (Domain Name
System) A hierarchical system of host naming that groups TCP/IP hosts into categories. For
example, in the Internet naming scheme, names with .com extensions identify hosts in
commercial businesses.
DNS spoofing The act of breaching the trust relationship by assuming the Domain Name System (DNS)
name of another system. This is usually accomplished by either corrupting the name
service cache of a victim system or by compromising a Domain Name Server for a valid
domain.
domain A group of computers or devices that share a common directory database and are
administered as a unit. On the Internet, domains organize network addresses into
hierarchical subsets. For example, the .com domain identifies host systems that are used
for commercial business.
download To transfer data from one computer to another, usually over a modem or network. Usually
refers to the act of transferring a file from the Internet, a bulletin board system (BBS), or
an online service to one's own computer.
DSX (Dynamic Security
Extension) A proprietary technology that is patented and works in the following way. The operating
system has a system call (or vector) table that contains memory address pointers for each
system call. These pointers point to a location in memory where the actual kernel code of
the system calls resides. DSX stores the address pointers for the security-sensitive system
calls and then redirects these pointers to the corresponding SECURED system call code,
which is located elsewhere in memory.