A redirect server is actually a person agent server that generates 3xx (redirection) responses to requests it receives, directing the customer to contact an alternate list of URIs. A redirect server enables proxy servers to direct SIP session invitations to exterior domains. Registrar[edit] As described while in the earlier point, http://buzzgram.de/die-evolution-der-kommunikation-eine-einfuhrung-in-sip-trunking-voip-handys-softphones-und-voip-telefonanlagen/