You will create two main types of variables in your PHP code: scalar and array. Scalar variables contain only one value at a time, and arrays contain a list of values, or even another array.The example at the beginning of this chapter created a scalar variable, and the code in this book deals primarily with scalar variables. You can find information on arrays in Appendix B, "Basic PHP Language Reference." When you assign a value to a variable, you usually assign a va....

Whether it’s because you have made a call using a mobile phone, received a message on your pager, checked your email from a PDA or even just seen an advert related to it, we have all come across a wireless data or voice network!If a user, application or company wishes to make data portable, mobile and accessible then wireless networking is the answer. A wireless networking system would rid of the downtime you would normally have in a wired network due to cable problems. ....

Log files track the activity on a computer so administrators can see who has used the computer, what they did, how long they stayed connected, and where they came from. Since a log file can also record the activity of an unauthorized intruder, much like a surveillance camera can record a burglar breaking into a store, hackers look for the log file as soon as they get access into the computer. Script kiddies often delete the log files to prevent the administrator from seeing ex....

An SMTP (Simple Mail Transfer Protocol) server is a machine that transports mail, just like a Web server is a machine that displays Web pages when requested. An SMTP server is sometimes referred to as an outgoing mail server, which brings me to the point—you need one in order to complete the exercises in this chapter. On Linux/UNIX, Sendmail and Qmail are popular packages. On Windows, the SMTP service in the Windows NT Service Pack, or the service built into....