Forum Moderators: DixonJones
The answer is basically "yes", but it all depends on what web server you are using (eg IIS or Apache); and what access _you_ have to the computer itself.
For example, if you are running Apache, and either you have control of the server or have permissions to use a .htaccess file in the root of your website then you can block IP's by adding DENY FROM entries in .htaccess.
See the Apache .htaccess Tutorial [httpd.apache.org] for more information.