5
Technology Introduction
Introduction
(continued)
Introduction to Broadband Router Technology
A router is a device that forwards data packets from a source to a destination.
Routers forward data packets using IP addresses and not a MAC address. A
router will forward data from the Internet to a particular computer on your LAN.
The information that makes up the Internet gets moved around using routers.
When you click on a link on a web page, you send a request to a server to show
you the next page. The information that is sent and received from your computer
is moved from your computer to the server using routers. A router also
determines the best route that your information should follow to ensure that the
information is delivered properly.
A router controls the amount of data that is sent through your network by
eliminating information that should not be there. This provides security for the
computers connected to your router, because computers from the outside
cannot access or send information directly to any computer on your network.
The router determines which computer the information should be forwarded to
and sends it. If the information is not intended for any computer on your network,
the data is discarded. This keeps any unwanted or harmful information from
accessing or damaging your network.
Introduction to Firewalls
A firewall is a device that sits between your computer and the Internet that
prevents unauthorized access to or from your network. A firewall can be a
computer using firewall software or a special piece of hardware built specifically
to act as a firewall. In most circumstances, a firewall is used to prevent
unauthorized Internet users from accessing private networks or corporate LAN’s
and Intranets.
A firewall watches all of the information moving to and from your network and
analyzes each piece of data. Each piece of data is checked against a set of
criteria that the administrator configures. If any data does not meet the criteria,
that data is blocked and discarded. If the data meets the criteria, the data is
passed through. This method is called packet filtering.
A firewall can also run specific security functions based on the type of application
or type of port that is being used. For example, a firewall can be configured to
work with an FTP or Telnet server. Or a firewall can be configured to work with
specific UDP or TCP ports to allow certain applications or games to work
properly over the Internet.
