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SECURITY
THE
FACTS Security Solutions. Markets,
licenses, and supports a family
of network security software
products designed to provide
comprehensive security to computer
networks, including Internet
based systems and internal networks
and computing resources. The
security software products enables
an organization to protect its
computer networks from internal
and external attacks, and to
secure organizational communications
over such internal networks
and the Internet. Products include
distributed, host resident firewalls:
We
are here to help you develop
your organisations understanding
and competence to address this
significant business issue.
As an introduction we have brought
together information relating
to many relevant security topics.
These topics include Firewall
and the IPSEC.
Encryption has also been a key
technology in 2000. All facets
of networking and computing
depend on the security of information.
VPNs, electronic commerce, web-based
access to sensitive information,
and even e-mail require the
ability to hide data from prying
eyes as it passes over public
networks or unsecured servers.
The
maturation of these three technologies
during 2000 helped to drive
the Internet economy forward
and will continue to do so.
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.
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Application gateway: Applies
security mechanisms to specific
applications, such as FTP and
Telnet servers. This is very
effective, but can impose a
performance degradation.
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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.
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Proxy server: Intercepts all
messages entering and leaving
the network. The proxy server
effectively hides the true network
addresses.
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In practice, many firewalls
use two or more of these techniques
in concert. A firewall is considered
a first line of defence in protecting
private information. For greater
security, data can be encrypted.
IPSEC - Short for IP Security,
IPSEC is a set of protocols
developed by the IETF to support
secure exchange of packets at
the IP layer. IPSEC has been
deployed widely to implement
Virtual Private Networks (VPNs).
IPSEC
supports two encryption modes:
Transport and Tunnel. Transport
mode encrypts only the data
portion (payload) of each packet,
but leaves the header untouched.
The more secure Tunnel mode
encrypts both the header and
the payload. On the receiving
side, an IPSEC-compliant device
decrypts each packet.
For
IPSEC to work, the sending and
receiving devices must share
a public key. This is accomplished
through a protocol known as
Internet Security Association
and Key Management Protocol/Oakley
(ISAKMP/Oakley), which allows
the receiver to obtain a public
key and authenticate the sender
using digital certificates.
UDP
PORT SCAN: UDP-based port scanning
allows an attacker to gain information
about UDP services running on
a target machine. As with TCP
port
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