Chapter 3 Flashcards
A (Address) record
A type of DNS data record that maps the IPv4 address of an Internet-connected device to its domain name.
AAAA (Address) record
A type of DNS data record that maps the IPv6 address of an Internet-connected device to its domain name. Pronounced “quad-A record.”
address translation
A technique in which IP addresses used on a private network are assigned a public IP address by a gateway when accessing a public network.
anycast address
A type of IPv6 address that represents a group of interfaces, any one of which (and usually the first available of which) can accept a transmission. At this time, anycast addresses are not designed to be assigned to hosts, such as servers or workstations, but rather to routers.
APIPA (Automatic Private IP Addressing)
A service available on Windows computers that automatically assigns the computer’s NIC a link-local IPv4 address in the range of 169.254.0.1 through 169.254.255.254.
authoritative server
The authority on computer names and their IP addresses for computers in their domains.
broadcast
A message that is read by every node on a network.
broadcast domain
Logically grouped network nodes that can communicate directly via broadcast transmissions. By default, switches and repeating devices, such as hubs, extend broadcast domains. Routers and other Layer 3 devices separate broadcast domains.
caching DNS server
A server that accesses public DNS data and caches the DNS information it collects.
canonical name
The true name of a server, such as www.example.com, as opposed to one of many alias names a server might have, such as ns1.example.com.
classful addressing
An IP addressing convention that adheres to network class distinctions, in which the first 8 bits of a Class A address, the first 16 bits of a Class B address, and the first 24 bits of a Class C address are used for network information.
CLI (command-line interface)
A graphic-free user interface, such as the Command Prompt application in Windows, where technicians can enter commands more quickly and with more flexibility than in a GUI (graphical user interface) environment.
CNAME (Canonical Name) record
A type of DNS data record that holds alternative names for a host.
default gateway
The gateway device that nodes on the network turn to first for access to the outside world.
device ID
See extension identifier.
DHCP (Dynamic Host Configuration Protocol)
An Application layer protocol in the TCP/IP suite that manages the dynamic distribution of IP addresses on a network.
DHCP pool
The predefined range of addresses that can be leased to any network device on a particular segment.
DHCP reservation
An IP address that is set aside by a DHCP server for a specific network client, which is identified by its MAC address.
DHCP scope
A shortage of available IP addresses on a network so that no new clients can connect to the network.
DHCPv6
The version of DHCP used with IPv6.
dig (domain information groper)
A utility available on Linux and macOS that provides more detailed domain information than nslookup. Use dig to query DNS nameservers for information about host addresses and other DNS records.
DKIM (DomainKeys Identified Mail)
An authentication method that uses encryption to verify the domain name of an email’s sender.
DMZ (demilitarized zone)
An area on the perimeter of a network that is surrounded by two firewalls—an external firewall that is more porous to allow more types of access, and an internal firewall that is more hardened to provide greater protection to the internal network.
DNAT (Destination Network Address Translation)
A type of address translation in which a gateway has a pool of public IP addresses that it is free to assign to a local host whenever the local host makes a request to access the Internet.