If you want to restrict who can access your server you can add a set of restrictions as follows:
The default if you don't specify anything is equivalent to ALLOW all. If you do add any restrictions, then the default becomes DENY all, and you must explicitly enable access from particular sites. Thus the above only allows access from machines with addresses `` 128.16. something. something'', with the exception of machines with address `` 128.16.64. something''.