User guide

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DH Group. Diffie-Hellman is a public key algorithm used between two sys-
tems to determine and deliver secret keys used for encryption. Groups 1, 2
and 5 are supported. Also, see Diffie-Hellman listing.
DHCP. Dynamic Host Configuration Protocol. A network configuration proto-
col that lets a router or other device assign IP addresses and supply other
network configuration information to computers on your network.
dial on demand. Communication circuit opened over standard telephone
lines when a network connection is needed.
Diffie-Hellman. A group of key-agreement algorithms that let two computers
compute a key independently without exchanging the actual key. It can gen-
erate an unbiased secret key over an insecure medium.
diffserv. Differentiated Services. A method for controlling Quality of Service
(QoS) queue priority settings. It allows a Gateway to make Quality of Service
(QoS) decisions about what path Internet traffic, such as Voice over IP
(VoIP), should travel across your network.
domain name. Name identifying an organization on the Internet. Domain
names consists of sets of characters separated by periods (dots). The last
set of characters identifies the type of organization (.GOV, .COM, .EDU) or
geographical location (.US, .SE).
domain name server. Network computer that matches host names to IP
addresses in response to Domain Name System (DNS) requests.
Domain Name System (DNS). Standard method of identifying computers
by name rather than by numeric IP address.
DSL. Digital Subscriber Line. Modems on either end of a single twisted pair
wire that delivers ISDN Basic Rate Access.
DTE. Data Terminal Equipment. Network node that passes information to a
DCE (modem) for transmission. A computer or router communicating through
a modem is an example of a DTE device.
DTR. Data Terminal Ready. Circuit activated to indicate to a modem (or
other DCE) that the computer (or other DTE) is ready to send and receive
data.