[OpenSER-Users] Why every body return "404 Not Found" instead of "480 Not Available"?

Hi, after a large discussion in sip-implementros maillist I realize that a proxy/location server shouldn't reply "404" if a callee DOES exist but it's not registered in that moment. In fact: 480 Temporarily Unavailable [...] This status is also returned by a redirect or proxy server that recognizes the user identified by the Request-URI, but does not currently have a valid forwarding location for that user. 404 Not Found The server has definitive information that the user does not exist at the domain specified in the Request-URI. [...] Why then every body suggest to reply "404 Not Found" when "lookup(location)" returns -1? For example, the "registrar" module doc suggests it: Example 1-22. lookup usage lookup("location"); switch ($?) { case -1: case -3: sl_send_reply("404", "Not Found"); exit; case -2: sl_send_reply("405", "Not Found"); exit; }; Best regards. -- Iñaki Baz Castillo ibc(a)in.ilimit.es