Syngress - Eleventh Hour Network+ Exam N10-004 Study Guide (11 ...

50 CHAPTER 3 Network Devices
Proxy servers can:
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Cache information going to/from the Internet.
Act as the physical gateway between the Internet and company network.
Be configured with filtering for determining if traffic is to be allowed.
Intrusion Detection System
IDS is designed to inspect and detect the kinds of traffic or network behavior patterns
that match known attack signatures or that suggest potential unrecognized
attacks may be incipient or in progress.
It is used as a specialized tool that knows how to read and interpret the contents
of log files from routers, firewalls, servers, and other network devices. Although
such devices tend to operate at network peripheries, IDS systems can detect and
deal with insider attacks and external attacks.
OTHER DEVICES AND TECHNOLOGIES
Various devices are used to manage a network and provide additional features
that make the network safer and more functional in day-to-day use. Examples of
other devices and technologies include the following:
■ Gateways A gateway is a bridge connecting two dissimilar systems.
■ Default gateways and subnetworks Default gateways are routers that are
used to forward data packets with a destination IP address not on the local
subnet. The default gateway forwards the data packet to other gateways until
the packet is ultimately delivered to a gateway connected to the intended
destination.
■ Wireless Wireless networks require minimal cabling as data is transmitted
over the air using wireless adapters and wireless routers. Computers using
wireless NICs use a transceiver that sends and receives signals over the air
to a wireless router or hub. The wireless router is an access point providing
a method of communication that the computers with wireless NICs can
connect to.
■ Network attached storage (NAS) NAS devices are devices that are dedicated
to providing storage of data on the network. NAS uses hard disks for storage,
but instead of being installed on a server, the storage device is accessed
through its own network address.
■ Domain name service (DNS) Server DNS is a service that maps IP
addresses to names. A HOSTS file can be used to perform the same function,
but is a local text file that must be kept up-to-date. DNS provides the same
functionality through a centralized database.
■ Dynamic Host Configuration Protocol (DHCP) Server DHCP is a
broadcast-based protocol that is used to automatically assign TCP/IP
addressing information to computers. DHCP requires a DHCP Relay server