Trend Micro™ Network VirusWall™ Enforcer 2500 Administrator’s Guide
G–4
objects. Each object is an essential data about a
particular aspect of the managed Network
VirusWall Enforcer 2500 device, such as the
number of packets received or memory utiliza-
tion statistics.
NAT
See Network Address Translation.
Network Address Translation
Network Interface Card
Also known as NIC. The term refers to an
expansion board inserted into a computer so the
computer can connect to a network. Most NICs
work only with a particular type of network, pro-
tocol, and media, although some can serve mul-
tiple networks.
Network segment
A section of a network that falls within the
bounds of bridges, routers, or switches. Dividing
an Ethernet into multiple segments is one of the
most common ways of increasing available
bandwidth on the LAN. If segmented correctly,
most network traffic remains within a single seg-
ment, enjoying the full 10 Mbps bandwidth. Hubs
and switches connect each segment to the rest
of the LAN.
Network Time Protocol
Also known to NTP. The term refers to an Inter-
net standard protocol (built on top of TCP/IP)
that assures accurate synchronization to the mil-
lisecond of computer clock times in a network of
computers.
Network virus
The type of threat that Network VirusWall
Enforcer 2500 devices can detect, eliminate,
and contain.
A virus spreading over a network is not, strictly
speaking, a network virus. Only some of the
known malware programs, such as worms, are
actually network viruses. Specifically, network
viruses use network protocols, such as TCP,
FTP, UDP, HTTP, and email protocols to repli-
cate. They often do not alter system files or
modify the boot sectors of hard disks. Instead,
network viruses infect the memory of client
machines, forcing them to flood the network with
traffic, which can cause slowdowns and even
complete network failure. Because network
viruses remain in memory, they are often unde-
tectable by conventional file I/O based scanning
methods.
NIC
See network interface card.
NMS
In the SNMP management architecture, one or
more computers on the network act as a net-
work management station (NMS) and poll the
managed devices to gather information about
their performance and status.
NTKD
Refers to scan engine used by products running
on Windows NT, 2000, or XP machines.Opera-
tion Mode
The Network VirusWall Enforcer 2500 Preconfig-
uration menu (menu number 3) that provides the
options to configure the failopen, failover, and
port redundancy settings.
NTP
OSI model
Short for Open System Interconnection model.
This model defines a networking framework for
implementing protocols in seven layers. Control
is passed from one layer to the next, starting at
the application layer in one station, proceeding
to the bottom layer, over the channel to the next
station and back up the hierarchy. Network
VirusWall Enforcer 2500 works with L2 and L3
devices.
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