## 8.6. Summary

If you remember one thing from this chapter, it should be that you should never trust the user or the browser. Always double-check your input, avoid the shell, and use taint mode. Also, your system should be designed so that if crackers do break into your web server, they do not gain much. Web servers are frequent targets because they are the most visible system a company has, as well as the most easy to break into (though following the suggestions in this chapter certainly helps). Therefore, do not store important data (e.g., unencrypted credit card numbers) on the machine. Likewise, avoid creating trust relationships between the web server and other machines. Your network should be configured so that someone who manages to crack into your web server should not have easy access to the rest of your network.

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