1.4.5.5.9.2. Supported Authentication Methods
MethodSupportedNote
BasicYesBeing routed
Bearer (OpenID)YesBeing routed through
Negotiate (Kerberos)YesRedirecting...

The " allowproxy = true " setting must be explicitly enabled for the server to evaluate X-Forwarded-For headers. Without this setting, all requests are treated as direct client connections.