How can I hide the SharePoint CMS from public view?

hi… I am new to SharePoint and was given the task to administer a SharePoint 2007 site.

The first complaint I have received is that they were able to view the CMS publicly. (e.g. which is http://domainname/contents)

Visitors are landing on the link via a Google search. Although the visitor cannot edit unless they know the credentials. Is there a way that it does not show publicly?

Thanks so much