On this article series we will review the concept of firewalls, gateways and
routers. Specifically, we will explore the installation, migration and administration
secrets of Microsoft Internet Security and Acceleration Server (ISA) to provide
an easy and hands-on approach for firewall implementers and security managers.
Types of Firewalls
Firewalls vary in their security protection and defense approach. Generally,
they run in dedicated hosts or hardware devices that are directly connected to
different network segments. A connection to the firewall is established each time
a client wants to send data to a server on the separated network.
Join our new forums at WebProWorld! Ask your toughest questions
or help your peers solve their issues. |
|
|
The main technical distinction between firewalls is the mechanism that they
use to pass traffic from one segment to another. Lower-level firewalls perform
operations on the first layers of the OSI model (Open Systems Interconnect) which
usually makes them faster, while Higher-level firewalls usually analyze more information
about the connection, such as a client connection to a specific site.
There are two types of firewalls. Network Layer firewalls are commonly the
traditional and simple routers. They make their decisions based on the source,
destination addresses and ports in individual connections. These firewalls are
not able to make decisions about what the connection contains and where it came
from. Modern Network-layer firewalls now maintain internal information about the
state of the connection and where it is coming from.
Application-level firewalls do not permit direct traffic between networks.
They perform logging and auditing functions on each connection that passes through
them. Proxy Servers are commonly used to perform logging and access control for
applications between different networks. Application layer firewalls are also
commonly used as network address translators. Applications use Application-level
firewalls to mask the origin of their connection and transparently communicate
with the separate network segment.
Internet Security and Acceleration (ISA) Server: A Corporate Firewall
Whether installed as a dedicated security component, or as an integrated firewall
and caching server, ISA Server provides a multi-layered enterprise firewall that
helps protect networks from hacker attacks. ISA Server provides several security
technologies including: unified server management, packet filtering, intrusion
detection and secure publishing. All these features built on top of Windows 2000,
simplify network security management tasks and provide a complete and reliable
firewall server.
Click
Here to Read the Full Article
About the Author:
Considered to be a leading expert in Information Security, Leonard Loro
holds more than 10 years of experience maximizing the security, maintenance, and
control around IT systems and computer networks. You can contact Leonardo Loro
about "An Introduction to Network Firewalls and Microsoft Internet Security
and Acceleration Server" at leoloro@2000trainers.com.
|
By 
