Alcatel-Lucent OmniAccess 700, Cli Configuration Manual

Page: 675 / 1193

Network Security - An overview
Except on the first page, right running head:
Heading1 or Heading1NewPage text (automatic)
649
Alcatel-Lucent
Beta Beta
CLI Configuration Guide
N
ETWORK
S
ECURITY
T
ERMINOLOGIES
This section explains the Network Security Terminologies.
•
“Gateway”
•
“Application Level Gateway (ALG)”
G
ATEWAY
A gateway is an internetworking system used to connect two disparate network
technologies and achieve seamless interconnectivity. Gateways typically operate
on one or more layers of the OSI data model. Depending on the function intended
for, they can operate from the application layer to link layer. A common type is a
protocol gateway used to connect networks running different network or
application protocols (e.g. TCP/IP, IPX). Because a network gateway can appear
at the edge of the network, it is likely to implement related functions like firewalling
on the gateway.
A
PPLICATION
L
EVEL
G
ATEWAY
(ALG)
An ALG has the capability to conduct stringent packet inspection and thereby
augment the security infrastructure. Besides using a specialized program for each
type of application or service that needs to pass through the firewall, ALGs look
for altered data, potentially harmful traffic, data appropriateness, and also have
the capability to log these.
Figure 18: Depicting ALG Scenario