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The whole reason that data should be encrypted across networks is due to the fact that just about any system administrator can view data that passes through his system. The Internet is just a network of networks, and all along the path between you and the server you re communicating with, there could be someone listening. This eves-dropping on network traffic is generally referred to as sniffing. When data is sent across the Internet it is broken down into chewable pieces called packets. Now the packets each have the address they re trying to get to and the order in which they re supposed to be read in, encoded on them. Each individual packet will find its own way between you and the web site you re surfing. If somewhere along that line someone makes a copy of a packet or two, of yours, they might be able to find out information that you don t want them to know. This technique has been used to gain access to systems by sniffing usernames and passwords off the network. It has also found some publicity in individuals identities being stolen and huge debts being run up on their credit cards. Sniffing tools have been developed for the purposes of debugging network configurations and such. There is always going to be the ability for a malicious person to receive information that wasn t intended for them. Due to this ability, it reinforces the importance that strong encryption has on Internet commerce and the importance that it will continue to have into the future. Firewalls Other than information that is traveling outside the corporate Intranet there isn t too much worry about network security. Many corporations are setting up filtering routers or Unix hosts that filter the network traffic coming into their system. This method of filtering network traffic is called a firewall. A firewall is a combination of hardware and software components that provide a choke point between a trusted network and an untrusted network such as the Internet. The firewall provides a certain level of control as to what can go between the two networks. 2 As sniffing can be used maliciously by an attacker, it has also started to become a tool used by corporations to monitor traffic flow across their networks. Corporations have been trying to cut back on web surfing by employees and extraneous emails. The access to the Internet has been, counter productive to some employees. The firewall provides an excellent point for network monitoring to take place. By monitoring the network traffic the corporation can be sure that the employees aren t wasting time or downloading anything that might be dangerous to the system. Recently there has been a scare about a macro virus named Melissa. A computer virus is a program that, when executed, tries to duplicate itself. They generally either infect the boot record of a disk or attach themselves to some kind of executable file. In this manner they have ample opportunity to be executed. The Melissa virus was a Microsoft Office Macro that was designed to spread using the names in the victims Outlook address book. It would email itself to the first fifty entries where once opened by the recipients, it would start the process over again. The computer virus can cause big losses in productivity from downed systems and corrupted data. For the virus to duplicate it tries to copy itself to a new location and in doing so can cause data to be over written. In systems that are Unix based there isn t too much of a problem with viruses. The design of the operating system doesn t give programs the freedom to roam as much as the PC architecture does. On Windows based machines there should be a current virus scanner running, to help keep virus losses to a minimum. The scanner should

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