FREE online courses on Corporate Espionage - What can be
done about it - What are Firewalls
If
your PC is a stand-alone unit, you don't need a firewall.
But if you access the Internet, and especially if you have a LAN or WAN, and
more especially if you have market/industry/ finance-sensitive data on your
system/network, YOU NEED A
FIREWALL! Particularly when:
Your computers
files need to be accessed remotely across the internet
You are operating
any sort of server
You use any type
of internet-based remote control/access program
You want to
MONITOR your internet connection for attempts at intrusion
You want to
protect yourself from “inside the wall” TROJAN HORSE PROGRAMS.
A firewall ABSOLUTELY ISOLATES your computer
from theinternet, using a “wall of code” that
inspects each individual packet of data as it arrives, at EITHER SIDE of
the firewall (in bound or outbound) and determines whether it should be
allowed to pass, or blocked!
When two machines establish an
Internet connection, packets of data are exchanged.
Receiving machine sends back
“acknowledgement packet”
All “information packets”
contain the IP address and port number. IP is the Internet provider i.e. ----
complete source and destination address ----- and ‘port' is the particular
machine where the conversation is happening.
The ‘firewall' program
effectively filters out unauthorized packets of information i.e. those whose ID
address etc. do not match those authorized to make connection. The port rejects
the very first packet, and thereafter, becomes invisible to subsequent data
packets.
Specific entry can be limited
to a particular (set of) port(s). Thus, any Trojan Horse packet getting past
and establishing a ‘listening port' inside your machine will languish
ineffectually, since no passing scanner could detect the Trojan horse on the
opposite side of the firewall, leave alone establish contact with it.
Incoming packets of
information wishing to establish an unauthorized connection, will be ignored,
but the firewall will allow your outgoing packets to pass through.
“Application level” filtering
allows the firewall to not just reject packets, depending upon source and
destination addresses, but INVOLVE ITSELF IN THE ACTUAL DIALOG TAKING PLACE.
It can detect a password snuffers or cracker package and automatically “black
list” source/destination address to prevent future access attempts (as does the
Black Ice Defender Firewall).
Try Zone Alarm 2.0, 100% free
for the individual user, down loadable from the internet or try other
proprietary firewalls such as:
