Welcome to WebmasterWorld Guest from 22.214.171.124
In order for this to work, HostNameLookups must be enabled in your server configuration.
Many hosts DO NOT enable this option, because a host name lookup requires that your server send a Reverse-DNS request to the DNS system for every single page/image/script HTTP request that your server receives. This adds considerably to the load on your server and on the host's network. Because your server must wait for a response to its RDNS request before serving anything to your visitor, it slows down your server as well. If the RDNS lookup fails, then your server may 'hang' for a long time, and your visitor will think that your site has failed.
Therefore, you may wish to use IP-address-based access control:
Deny from 126.96.36.199
[edited by: jdMorgan at 3:46 pm (utc) on Dec. 22, 2006]