The de-facto standard network protocol for the 21st century is TCP/IP version 4, although
version 6 has been available for some time now.
Networks are generally divided into two distinct categories.
Local Area Networks (LANs) - which connect devices inside your office together and sometimes called private networks and allow the sharing of local resourdces
such as data files, music, printers, projectors, scanners etc..
Wide Area Networks (WANs) - which connect your device or LAN to the rest of the world. These are often referred to as public
A third term often heard is Virtual Private Network (VPN).
This is where two LANs are linked together over the public network in an encrypted 'tunnel" and can be used to link two or more offices
together to form one logical network.
The advantages of being connected to the Internet are almost beyond count. Without it there would be no Email, no World Wide Web, no VPNs and no remote access.
It also provides hackers, spammers and viruses opportunity to enter your systems which is why firewalls, both hardware and software are essential.
Ask WDC for more information on defence from hostile attack.