How can I control who gets access to proxy services?

You can control who can access your proxy via the normal control block using the following example:

              
   <Directory proxy:*>
           
   order deny,allow
            
   deny from [machines you'd like not to allow by IP address or name]
             
   allow from [machines you'd like to allow by IP address or name]
            
   </Directory>
            

A <files> block will also work.