You can add sites that you want blocked using the User Black List functions.

If you are a power user and experienced using Regular Expressions, you can add a regex to your blacklist as well.

Blacklist items can also be added on the Query Log page. Every log entry has an “Action” button in the Action column. If you see something in the log that you want blocked, just click on the button and it will be added to the blacklist.

When adding a top level domain like “google.com”, you will also need to add "www.google.com". In this case, google.com would be referred to as the “top level domain”, “TLD” or just the “domain”. WWW would be referred to as the “sub-domain”. Both are FQDNs or “fully qualified domain names”. FQDN means that the domain is properly formatted and can be resolved by a DNS server.

There is an easier way to add a domain and ALL sub-domains that it may have. That is to add it as a wildcard domain. So, if you added “google.com' as a wild card domain, it will also block "www.google.com", "images.google.com", "video.google.com", "search.google.com", etc.

Blacklists are global in scope. Any domain entered into the blacklist will be blocked from all clients, regardless of your group management settings.