Filtering Destinations

Dear friends:

I've discovered recently that a significant load on our caching servers,
running SQUID, results from the use of them to access local information
servers. We have asked users to setup their browsers to don't use
proxies for local servers.

Now, I'm asking you about the following: How can I setup SQUID in order
to deny any access though it to local servers. Is it possible?

Thanks in advance by any help.
Best regards.

P.S. This is my second attempt to get an answer from this list. Sorry!

-- 
Fernando Cozinheiro
System & Network Administrator
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Universidade de Aveiro                      Phone:   +351 34 370345
Centro de Informatica e Comunicacoes        Telefax: +351 34 370214
3810 Aveiro                                 Email: cooker@ci.ua.pt
Portugal                                    http://sweet.ua.pt/~cooker/