|
What
is a Firewall?
A system designed to prevent unauthorized access
to or from a private network.
Firewalls can be implemented in both hardware
and software,
or a combination of both. Firewalls are frequently
used to prevent unauthorized Internet
users from accessing private networks connected to the
Internet, especially intranets.
All messages entering or leaving the intranet pass
through the firewall, which examines each message and
blocks those that do not meet the specified security
criteria.
There are several types of firewall techniques:
- Packet filter: Looks at each packet
entering or leaving the network and accepts or
rejects it based on user-defined rules. Packet
filtering is fairly effective and transparent to
users, but it is difficult to configure. In
addition, it is susceptible to IP
spoofing.
- Application gateway: Applies security
mechanisms to specific applications, such as FTP
and Telnet
servers. This is very effective, but can impose a
performance degradation.
- Circuit-level gateway: Applies security
mechanisms when a TCP
or UDP
connection is established. Once the connection has
been made, packets can flow between the hosts
without further checking.
- Proxy server: Intercepts all messages
entering and leaving the network. The proxy
server effectively hides the true network
addresses.
In practice, many firewalls use two or more of
these techniques in concert.
A firewall is considered a first line of defense in
protecting private information. For greater security, data
can be encrypted
ref: http://www.webopedia.com/TERM/f/firewall.html
Don't be confused, let
CTSSG help you determine which type of firewall is
right for your needs. Our Certified Firewall
Instructors will help you find the right solution and
assist you with the installation if needed.
|
