I read your magazine regularly and find it very useful.
I want to develop expertise in the area of network security,
and Im specifically interested in Firewalls. Is
a Firewall the best security option?
K. Sinthanai Sirpi
K. Sinthanai Sirpi,
Thank you for your letter. I am glad that the magazine
has been of interest and utility to you. A Firewall
is a system designed to prevent unauthorized access
to or from a private network. It can be implemented
in both hardware and software, or a combination of both.
Firewalls are frequently used to prevent unauthorized
users from accessing private networks connected to the
Internet. It is considered a first line of defense in
protecting private information. For greater security,
data can be encrypted. Following are the types of firewalls:
Packet filter: Looks at each packet entering
or leaving the network and accepts or rejects it based
on user-defined rules.
Application gateway: Applies security mechanisms to
specific applications like FTP and Telnet servers.
This is very effective, but can impose some performance
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.
A Firewall is only a part of a total security solution.
A complete solution will typically consist of antivirus
programs, Firewalls, intrusion-detection systems, along
with management policies.
I am the Superintendent Engineer at the Irrigation Department
of Uttaranchal in Dehradun. We are working on a project
called 'Maneri Bhali' and the site is 200 km away from
our office. We have offices spread over 13 districts
in Uttaranchal and communication between them is a challenge.
I saw your article on VSATs on your website and Im
interested in exploring the possibility of installing
a VSAT. Can you let me know the various uses of VSAT,
details of the hardware necessary for installation and
Irrigation Department, Uttaranchal
I am glad that the article was of use to you. In a reply
to an earlier letter, Joyjit Chatterji at Comsat Max,
a VSAT solution provider has suggested the following:
It is possible today to provide Internet access anywhere
across the country on a VSAT. The solution involves
installing, at the client location a VSAT which comprises
a 1.2 m antenna and associated electronics. The indoor
electronic unit has full routing capabilities and connects
to a single PC or LAN. The traffic travelling to and
from the client location is carried on a satellite link
to our master earth station in New Delhi which has a
thick pipe to the Internet through VSNL on fiber. We
have multiple gateways and offer guaranteed access of
99.5 percent of the time calculated annually. The advantages
of Internet using VSAT are anywhere and anytime availability,
high uptime, and consistent performance.