Glossary
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Assigning fixed IP addresses makes sense in cases where
a local network has a sufficiently large pool of IP address-
es available, or when a computer is always supposed to
be accessible at a certain address (such as a web server or
e-mail server).
Firewall
A firewall protects a computer or local network against at-
tacks from the Internet.
Most firewalls work with packet filters, which merely
check the IP addresses and port numbers of incoming and
outgoing data packets and filter the packets according to
prescribed rules.
Some firewalls also integrate additional concepts like IP
masquerading and NAT to decouple data traffic by distin-
guishing strictly between the internal and external net-
work.
Especially effective firewalls go even further, analyzing
and evaluating the contents of the packets and filtering
them according to prescribed rules. Such techniques may
also include a Stateful Packet Inspection Firewall, for in-
stance.
Firmware
Firmware designates software that is embedded in elec-
tronic devices. Firmware is saved in programmable com-
ponents within a device. Through the possibility of updat-
ing the firmware by computer at any time, manufacturers
enjoy great flexibility in reacting to the demands of the op-
erational environment, integrating new functions request-
ed by customers, and eliminating errors discovered after
production.
FTP
abbreviation for File Transfer Protocol
The File Transfer Protocol allows files to be exchanged be-
tween two computers operating in the Internet. Data ex-
change takes place via an FTP server and what is known as
an FTP client. The more convenient FTP clients are avail-
able as stand-alone software or are components of some
ISDN data transfer software; simple FTP clients are now in-
cluded in many web browsers.