You have or will have shortly a presence on the Internet available to anyone 24 hours a day, 7 days a week. While this constant availability is great for business, it also means that those with less‑than‑pure intentions can try to disrupt your site at any time.

Depending on who you talk to, individuals who attempt to disrupt websites and computer systems illegally might be called hackers, black hat hackers, crackers, or even script kiddies (less proficient individuals who rely on well‑known security issues and more commonly available hacking tools). In this book, I will refer to them all as hackers.

You may be thinking, "No one would bother messing with my little website devoted to pictures of my dog." Think again! You may not have credit card information or other private data stored in your account, but that won’t stop a hacker who decides they want to mess with your site. The simple fact that your site is available 24/7 on the Internet is a big draw. In addition, some...