Manipulating user agents in squid

  • Hello,

    So I was trying to follow this tutorial:

    then I saw there was a way to hide the user agent from people their browser I thought it could be usefull against tracking.
    but now I wonder how could I use this code:

       header_access User-Agent deny all
       header_replace User-Agent SecretBrowser/5.0 (iPhone; U; Commodore64; en)

    i've tried to use the code inside the advanced configuration under the textboxes on the start page of squid in pfsense:
    under "Custom Options (Before Auth)" and in "Custom Options (After Auth)" but it didn't seemed to work.

    Is there a way to get to the squid.conf?

    I had readed in some topics that the config was either hardcoded or was not persistent, how can I make these changes persistent?