You call Description:Information provided in the Via HTTP response header for proxied requests
Syntax:ProxyVia On|Off|Full|Block Default:ProxyVia Off Context:server config, virtual host Status:Extension Module:mod_proxy This directive controls the use of the Via: HTTP header by the proxy. Its intended use is to control the flow of of proxy requests along a chain of proxy servers. See RFC 2616 (HTTP/1.1), section 14.45 for an explanation of Via: header lines. * If set to Off, which is the default, no special processing is performed. If a request or reply contains a Via: header, it is passed through unchanged. * If set to On, each request and reply will get a Via: header line added for the current host. * If set to Full, each generated Via: header line will additionally have the Apache server version shown as a Via: comment field. * If set to Block, every proxy request will have all its Via: header lines removed. No new Via: header will be generated As example. You need to go back to school and Apache documentation needs serious updates. For non serious people such a documentation is ok.