ProxyVia
ProxyVia on|off|full|block Default: ProxyVia off Server config, virtual host
This directive controls the use of the Via: HTTP
header by the proxy. Its intended use is to control the flow of proxy
requests along a chain of proxy servers. See RFC2068 (HTTP 1.1) 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.