A second example of common Internet traffic is E-mail. E-mail has historically been the source of the most insecure traffic on all networks. The reason for this is the pervasiveness of human error and lack of education when accessing E-mail. A server can be set to reject unauthorized or malicious attempts at accessing it and the server will continue to do its job over and over. Humans, on the other hand, can be told what to do and what not to do but still ignore all warnings at the end of the day.
Humans are the notorious weak link on most systems.
A third example of Internet traffic is FTP traffic. Most companies now host FTP servers that allow for the transfer of files to and from the network. An FTP server that is left open or configured incorrectly compromises the entire system. Unprepared companies, perpetrators, and uneducated users are not the only ones to blame for the sudden rash of viruses on the Internet. Another factor that has led to a boom in malicious programs is the design of software and operating systems released to the market.