A firewall is a set of related programs, located at a network gateway
server, that protects the resources of a private network from users
from other networks. Basically, a firewall, working closely with a
router program, filters all network packets to determine whether to
forward them toward their destination.
A firewall is often installed away from the rest of the network so that
no incoming request can get directly at private network resources.
There are a number of firewall screening methods. A simple one is to
screen requests to make sure they come from acceptable (previously
identified) domain names and IP addresses. For mobile users, firewalls
allow remote access in to the private network by the use of secure
logon procedures and authentication certificates. For more information on Firewalls click here
