To preserve same-origin security policies in browsers and
prevent Host: header forgery by redirectors Squid rewrites
any Host: header in redirected requests.
If you are running an accelerator this may not be a wanted
effect of a redirector. This directive enables you disable
Host: alteration in reverse-proxy traffic.
WARNING: Entries are cached on the result of the URL rewriting
process, so be careful if you have domain-virtual hosts.
WARNING: Squid and other software verifies the URL and Host
are matching, so be careful not to relay through other proxies
or inspecting firewalls with this disabled.