☎️Phone SIP codes

SIP responses are the codes used by the Session Initiation Protocol for communication. We have compiled a list of all known SIP responses.

Code Status

Code	Name	Description
100	Trying	Extended search is being performed so a forking proxy must send a 100 Trying response.
180	Ringing	The Destination User Agent has received the INVITE message and is alerting the user of the call.
181	Call Is Being Forwarded	Optional; sent by the Server to indicate a call is being forwarded.
182	Queued	Destination was temporarily unavailable; the server has queued the call until the destination is available.
183	Session Progress	This response may be used to send extra information for a call which is still being set up.
199	Early Dialog Terminated	Sent by the User Agent Server to indicate that an early dialog has been terminated.
200	OK	Indicates that the request was successful.
202	Accepted	Indicates that the request has been accepted for processing, mainly used for referrals.
204	No Notification	Indicates that the request was successful but no notification will be received.
300	Multiple Choices	The address resolved to one of several options for the user or client to choose from.
301	Moved Permanently	The original Request-URI is no longer valid; the new address is given in the Contact header.
302	Moved Temporarily	The client should try the address in the Contact field.
305	Use Proxy	The Contact field specifies a proxy that must be used to access the requested destination.
380	Alternative Service	The call failed, but alternatives are detailed in the message body.
400	Bad Request	The request could not be understood due to malformed syntax.
401	Unauthorized	The request requires user authentication. This response is issued by UASs and registrars.
402	Payment Required	(Reserved for future use).
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 indicated location (User not found).
405	Method Not Allowed	The method specified in the Request-Line is understood but not allowed.
406	Not Acceptable	The resource is only capable of generating responses with unacceptable content.
407	Proxy Authentication Required	The request requires proxy authentication.
408	Request Timeout	Couldn’t find the user in time.
409	Conflict	User already registered (deprecated).
410	Gone	The user existed once but is not available here anymore.
411	Length Required	The server will not accept the request without a valid Content-Length (deprecated).
412	Conditional Request Failed	The given precondition has not been met.
413	Request Entity Too Large	Request body too large.
414	Request-URI Too Long	Server refuses to service the request; the Request-URI is longer than the server can interpret.
415	Unsupported Media Type	Request body is in an unsupported format.
416	Unsupported URI Scheme	Request-URI uses a scheme unknown to the server.
417	Unknown Resource-Priority	There was a resource-priority option tag, but no Resource-Priority header.
420	Bad Extension	Bad SIP protocol extension used; not understood by the server.
421	Extension Required	The server needs a specific extension not listed in the Supported header.
422	Session Interval Too Small	The request contains a Session-Expires header field with a duration below the minimum.
423	Interval Too Brief	Expiration time of the resource is too short.
424	Bad Location Information	The request’s location content was malformed or otherwise unsatisfactory.
428	Use Identity Header	The server policy requires an Identity header, and one has not been provided.
429	Provide Referrer Identity	The server did not receive a valid Referred-By token on the request.
430	Flow Failed	A specific flow to a user agent has failed, although other flows may succeed.
433	Anonymity Disallowed	The request has been rejected because it was anonymous.
436	Bad Identity Info	The request has an Identity-Info header and the URI scheme contained cannot be dereferenced.
437	Unsupported Certificate	The server was unable to validate a certificate for the domain that signed the request.
438	Invalid Identity Header	Server obtained a certificate used to sign a request but was unable to verify the signature.
439	First Hop Lacks Outbound Support	The first outbound proxy doesn’t support the “outbound” feature.
440	Max-Breadth Exceeded	If a SIP proxy determined a response context had insufficient Incoming Max-Breadth to carry out a desired parallel fork, and the proxy is unwilling or unable to compensate by forking serially or sending a redirect, that proxy MUST return a 440 response. A client receiving a 440 response can infer that its request did not reach all possible destinations.
469	Bad Info Package	If a SIP UA receives an INFO request associated with an Info Package that the UA has not indicated willingness to receive, the UA MUST send a 469 response containing a Recv-Info header field with Info Packages for which the UA is willing to receive INFO requests.
470	Consent Needed	The source of the request did not have the recipient’s permission to make such a request.
480	Temporarily Unavailable	Callee currently unavailable.
481	Call/Transaction Does Not Exist	Server received a request that does not match any dialog or transaction.
482	Loop Detected	Server has detected a loop.
483	Too Many Hops	Max-Forwards header has reached the value '0'.
484	Address Incomplete	Request-URI incomplete.
485	Ambiguous	Request-URI is ambiguous.
486	Busy Here	Callee is busy.
487	Request Terminated	Request has been terminated by BYE or CANCEL.
488	Not Acceptable Here	Some aspects of the session description of the Request-URI are not acceptable.
489	Bad Event	The server did not understand an event package specified in an Event header field.
491	Request Pending	Server has some pending request from the same dialog.
493	Undecipherable	Request contains an encrypted MIME body which the recipient cannot decrypt.
494	Security Agreement Required	The server has received a request that requires a negotiated security mechanism.
500	Server Internal Error	The server could not fulfill the request due to some unexpected condition.
501	Not Implemented	The SIP request method is not implemented here.
502	Bad Gateway	The server received an invalid response from a downstream server while trying to fulfill a request.
503	Service Unavailable	The server is in maintenance or temporarily overloaded and cannot process the request.
504	Server Time-out	The server tried to access another server while processing a request and did not receive a timely response.
505	Version Not Supported	The SIP protocol version in the request is not supported by the server.
513	Message Too Large	The request message length is longer than the server can process.
555	Push Notification Service Not Supported	The server does not support the push notification service specified in the pn-provider SIP URI parameter.
580	Precondition Failure	The server is unable or unwilling to meet some constraints specified in the offer.
600	Busy Everywhere	All possible destinations are busy.
603	Decline	Destination cannot or does not wish to participate in the call; no alternative destinations.
604	Does Not Exist Anywhere	The server has authoritative information that the requested user does not exist anywhere.
606	Not Acceptable	The user's agent was contacted successfully but some aspects of the session description were not acceptable.
607	Unwanted	The called party did not want this call from the calling party. Future attempts from the calling party are likely to be similarly rejected.