Check Authorization / WWW-Authenticate headers

Erich,

Do you want to block if the user provide a wrong password and is prompted again by the server?

when HTTP_REQUEST {
    if {[catch {set username [HTTP::username] }]} { set username ""}
    if { $username ne ""} { 
        set user_provided 1
    } else {
        set user_provided 0
    }

}

when HTTP_RESPONSE {
  if { ([HTTP::status] eq "401") && ($user_provided) } { HTTP::respond 403 content "Access is Denied!" }
}