To use: rename "htaccess.txt" to ".htaccess" and drop into the appropriate folder on your server.
Htwall is a collection of htaccess rules crafted to intercept common and pervasive exploits. Htwall is not meant to act as a comprehensive security measure. Let me repeat that in another way. If you are using htwall as your sole security measure then your website is insecure and will suffer malicious intrusions. Htwall is meant to act as an additional layer of security and a sanity check for those situations where one might be desired or when your options are limited by your host or server. Note before using htwall that a large and complicated htaccess file will cause a decrease of performance on your server, as the htaccess file must be compared against every url submission.
Visit the wiki for more information and guidelines on contributing to htwall.
Development of htwall has ended, support for htwall is nonexistent (but the wiki may help you if you run into problems).