SIP server response codes¶

Below is a list of selected response codes that may be sent from a SIP server. A full list can be found in ► IETF RFC 3261, section 21.

1xx – Provisional responses¶

100 Trying: This response indicates that the request has been received by the next-hop server and that some unspecified action is being taken on behalf of this call (for example, a database is being consulted).

403 Forbidden: The server understood the request, but is refusing to fulfill it.
404 Not Found: The server has definitive information that the user does not exist at the domain specified in the Request-URI. This status is also returned if the domain in the Request-URI does not match any of the domains handled by the recipient of the request.
408 Request Timeout: The server could not produce a response within a suitable amount of time, for example, if it could not determine the location of the user in time. The client may repeat the request without modifications at any later time.