Glossary
GL-10
Installing Cisco Intrusion Prevention System Appliances and Modules 5.0
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NAT
Native Address Translation. A network device can present an IP address to the outside networks that is
different from the actual IP address of a host.
Network Access
Controller
A component of the IPS. A software module that provides block and unblock functionality where
applicable.
never block address
Hosts and networks you have identified that should never be blocked.
never shun address
See never block address.
network device
A device that controls IP traffic on a network and can block an attacking host. An example of a network
device is a Cisco router or PIX Firewall.
NIC
Network Interface Card. Board that provides network communication capabilities to and from a
computer system.
NM-CIDS
A network module that integrates IPS functionality into the branch office router.
NMS
network management system. System responsible for managing at least part of a network. An NMS is
generally a reasonably powerful and well-equipped computer, such as an engineering workstation.
NMSs communicate with agents to help keep track of network statistics and resources.
node
A physical communicating element on the command and control network. For example, an appliance,
an IDSM-2, or a router.
NORMALIZER
engine
Configures how the IP and TCP normalizer functions and provides configuration for signature events
related to the IP and TCP normalizer.
NSDB
Network Security Database. A database of security information that explains the signatures the IPS
uses along with the vulnerabilities on which these signatures are based. The NSDB contains a
description for each attack signature that the sensor can detect.
NTP
Network Timing Protocol. Protocol built on top of TCP that ensures accurate local time-keeping with
reference to radio and atomic clocks located on the Internet. This protocol is capable of synchronizing
distributed clocks within milliseconds over long time periods.
NTP server
Network Timing Protocol server. A server that uses NTP. NTP is a protocol built on top of TCP that
ensures accurate local time-keeping with reference to radio and atomic clocks located on the Internet.
This protocol is capable of synchronizing distributed clocks within milliseconds over long time
periods.
NVRAM
Non-Volatile Read/Write Memory. RAM that retains its contents when a unit is powered off.
O
OIR
online insertion and removal. Feature that permits you to add, replace, or remove cards without
interrupting the system power, entering console commands, or causing other software or interfaces to
shutdown.
