Workshop

A device that converts (modulates) signals that the computer understands into signals that can be
accurately be transmitted over phone lines or other media. A modem can also convert the signals
back (demodulate) into their original form.
Morris Worm
See Internet Worm.
MTU
See maximum transmission unit.
multicast packet
A packet that’s destined for multiple (but not all) stations, possibly on multiple networks. Stations
that want to participate in multicasting must join a multicast group.
multihomed host
A host that has more than one network interface. Routers and firewalls typically have more than
one network interface.
NAUN
A Token-Ring station’s nearest addressable upstream neighbor. This is very important to know
for troubleshooting purposes.
NE2000
A very popular 10Mbps Ethernet network card, developed by Novell. Many network cards were
cloned from this, and it is now a de facto standard.
NetBIOS Protocol
A high-speed, lightweight transport protocol commonly used in local area networks, particularly
those running LAN Manager, Windows NT, or Windows 95.
netstat
UNIX command (also available in Windows) that shows the current TCP/IP connections and their
source addresses.
NetWare
A popular network operating system from Novell, Inc.
network analyzer
Hardware or software (or both) that captures and monitors network traffic. It decodes the traffic
into a form that can be read by humans.
network interface card (NIC)
An adapter card that lets the computer attach to a network cable.
network layer
Layer 3 of the OSI reference model. This layer provides the routing information for data, opens
and closes paths for the data to travel, and ensures that the data reaches it destination.
Network News Transfer Protocol (NNTP)
The protocol that controls the transmission of USENET news messages.
network operating system (NOS)
An operating system for networks, such as NetWare or Windows NT.
NIC
See network interface card.
NNTP
See Network News Transfer Protocol.