Protect Your Back
posted 21st June 2000

Its simple when you think of it, the trick is, to think of it - the Internet is a network, you can get to other computers..and they can get to yours. Like all computers, the Internet is all about playing with numbers, called IP (Internet protocol) numbers. You're reading this because you accessed a computer that has parts of it labelled with an IP number, for example 202.20.65.97 AND you had a number too, which allowed the information to find your computer on its way back.

Not all information is good information, some people with subconscious demons feel a need to access your computer and they can do that if they a. Know your IP number (given to you when you go online) b. Your computer has not protected itself software that provides what is commonly called a `firewall' between your computer and all the other computers online on the Internet. The most attactive targets for Internet delinquents is a large company with one or more permanent IP addresses, numbers that do not change each time the company's computers go online. When any network picks up a permanent IP address, it's like dangling a shiny lure in front of Internet sharks. They attack a permanent address because it's an easy target. It's true of both multinational corporations and small offices with cable or DSL modems. Hiding is the easiest and least expensive defense against intrusion attacks.

You can hide on the Internet through Network Address Translation, or NAT. This technology, which is priced from $6,000 camouflages networked systems with IP addresses that the bad guys can't see from the Internet. A NAT device translates between safe addresses on the LAN (local Area Network within the business office only) and its own permanent address. NAT is simple and effective against most intrusion threats, but it doesn't help you against denial-of-service or sophisticated attacks. If your resources are big or inviting, trouble is destined to find you. To keep trouble out, you need a firewall. They use several techniques to identify, check and filter packets (of digital data) going into and out of a network. Adding a firewall to your network takes expertise, so you might look for help from PlaNet technicians.

You can use the products as a single combined router (directs the network traffic) and firewall. Many administrators use a router for packet filtering and then a firewall to place Web servers and other Internet servers on a peripheral network, often called the demilitarized zone, or DMZ. The corporate-focused firewalls offer a special port for this peripheral network, and some of the small-office gateways can create a subnetwork through packet filtering. The important elements to look for in firewall systems include effectiveness and the availability of other features like a virtual private network (VPN). All worthwhile routers can create encrypted VPN connections for remote access. The most secure VPNs use the IPSec standard for encryption and data handling. IPSec is the wave of the future; but unless you're facing the possibility of a highly sophisticated threat, PPTP security is adequate and less difficult to set up in smaller networks. When it comes to you humble PC at home, subject to attacks from 12 year olds using Back Orrifice, a simple and free small firewall-type package can be installed. If you are not confident about what and how to do this you may want help. Not free help, but very good value for the security conscious - and who isn't these days?th