Force Users to use www.yourdomain.com not yourdomain.com.
If your having problems with cookies, and incoming links sometimes varying between www.example.com and example.com, which doesn’t help SEO. Use this quick fix to solve your problem.
Blocking users based on IP address from your website
Heres a really quick method of blocking users from accessing your website using the common mod_rewrite and .htaccess. For this method to work, you need to have FTP access to your website and be able to put this file in your main webpage directory or sub-directory that you want to limit access too.
Advanced Navigation II using Clean Urls
This tutorial will teach you how to implement clean SEO friendly web URLs. Example: Turning /index.php?page=register into http://www.domain.com/register/.