PHP and MySQL Web Development - P65: PHP and MySQL Web Development teaches the reader to develop dynamic, secure, commercial Web sites. Using the same accessible, popular teaching style of the first edition, this best-selling book has been updated to reflect the rapidly changing landscape of MySQL and PHP. | 292 Chapter 13 E-commerce Security Issues Occasional brief power failures are a fact of life in most places. In locations with harsh weather and above ground wires long failures occur regularly. If the continuous operation of your systems is important to you you should invest in an uninterruptible power supply UPS . A UPS that will power a single machine for 10 minutes will cost less than 300 . . Allowing for longer failures or more equipment can get expensive. Long power failures really require a generator to run air conditioning as well as computers. Like power failures network outages of minutes or hours are out of your control and bound to occur occasionally. If your network is vital it makes sense to have connections to more than one Internet service provider. It will cost more to have two connections but should mean that in case of failure you have reduced capacity rather than becoming invisible. These sorts of issues are some of the reasons you might like to consider co-locating your machines at a dedicated facility. Although one medium-sized business might not be able to justify a UPS that will run for more than a few minutes multiple redundant network connections and fire suppression systems a quality facility housing the machines of a hundred similar businesses can. Next In Chapter 14 we will look specifically at authentication allowing your users to prove their identity. We will look at a few different methods including using PHP and MySQL to authenticate your visitors. 14 Implementing Authentication with PHP and MySQL THIS CHAPTER WILL DISCUSS HOW TO IMPLEMENT various PHP and MySQL techniques for authenticating a user. Topics include Identifying visitors Implementing access control Basic authentication Using basic authentication in PHP Using Apache s .htaccess basic authentication Using basic authentication with IIS Using mod_auth_mysql authentication Creating your own custom authentication Identifying Visitors The Web is a fairly anonymous medium .