Glossary
FRITZ!Box Fon WLAN 7570 vDSL
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DNS
abbreviation for Domain Name System
Domain Name Service takes care of determining the IP ad-
dress for a given domain name. Domain Name Service is
running on every computer. It accepts the domain name en-
tered by a user and inquires about the corresponding IP ad-
dress at a DNS server known to the service. If a DNS server
cannot answer the inquiry itself, it can inquire about the IP
address (DNS resolution) at other DNS servers.
If the Domain Name Service receives negative information
from the DNS server (domain name not known), it can send
inquiries to other DNS servers it knows or return a corre-
sponding error message to the user. If it receives the de-
sired IP address instead, the application can use the IP ad-
dress to retrieve the destination desired by the user.
This hierarchical system of DNS servers is known as the Do-
main Name System. The addresses of the DNS servers at
which the Domain Name Service is to inquire by default
generally are handed over to the computer by the Internet
Service Provider automatically whenever a connection to
the Internet is established. In local networks addresses can
also be assigned via DHCP. Otherwise they must be entered
manually in the TCP/IP configuration of the PC by the user
or the system administrator.
DSL modem
A DSL modem connects a computer to the Internet via the
DSL line. In contrast to the analog modem, a connection via
the DSL modem does not mean that the telephone line is
busy.
DSL router
A combination of a DSL modem and a router is called a DSL
router.
dynamic DNS
abbreviation for Dynamic Domain Name System
Dynamic DNS is a service which allows a computer always
to be reached under the same domain name despite con-
stantly changing IP addresses. This means that even pri-
vate users have an economical way of placing their own In-
ternet offers on their computer at home.
