By default, Squid sends HTTP headers on every request that can give away information about your internal network. Here’s an example of these headers:
HTTP_VIA:1.1 proxyserver.local (squid/3.1.16)
That’s three pieces of information you may not want to give away: The host name of your proxy server, the version of Squid it’s running, and the IP address of the system that’s making the request via the proxy.
Fortunately, it’s simple (and does not apparently violate any standards) to make these headers more anonymous – just use these configuration directives in your squid.conf:
# Be more anonymous
That will change the headers to look more like this:
HTTP_VIA:1.1 proxy.local (squid)