SIP Response Codes
What Are Common SIP Responses?
Various SIP Responses are used during the setup and throughout the call to communicate information about failure reason, call state and update information such as caller ID. Below are the common SIP Responses.
1xx - Informational Responses
- 100 Trying
- 180 Ringing
- 181 Call Is Being Forwarded
- 182 Queued
- 183 Session Progress
2xx - Successful Responses
- 200 OK
- 202 accepted: It Indicates that the request has been understood but actually can’t be processed
3xx - Redirection Responses
- 300 Multiple Choices
- 301 Moved Permanently
- 302 Moved Temporarily
- 305 Use Proxy
- 380 Alternative Service
4xx - Client Failure Responses
- 400 Bad Request
- 401 Unauthorized (Used only by registrars or user agents. Proxies should use proxy authorization 407)
- 402 Payment Required (Reserved for future use)
- 403 Forbidden
- 404 Not Found (User not found)
- 405 Method Not Allowed
- 406 Not Acceptable
- 407 Proxy Authentication Required
- 408 Request Timeout (Couldn’t find the user in time)
- 409 Conflict
- 410 Gone (The user existed once, but is not available here any more.)
- 412 Conditional Request Failed
- 413 Request Entity Too Large
- 414 Request-URI Too Long
- 415 Unsupported Media Type
- 416 Unsupported URI Scheme
- 417 Unknown Resource-Priority
- 420 Bad Extension (Bad SIP Protocol Extension used, not understood by the server)
- 421 Extension Required
- 422 Session Interval Too Small
- 423 Interval Too Brief
- 424 Bad Location Information
- 428 Use Identity Header
- 429 Provide Referrer Identity
- 433 Anonymity Disallowed
- 436 Bad Identity-Info
- 437 Unsupported Certificate
- 438 Invalid Identity Header
- 480 Temporarily Unavailable
- 481 Call/Transaction Does Not Exist
- 482 Loop Detected
- 483 Too Many Hops
- 484 Address Incomplete
- 485 Ambiguous
- 486 Busy Here
- 487 Request Terminated
- 488 Not Acceptable Here
- 489 Bad Event
- 491 Request Pending
- 493 Undecipherable (Could not decrypt S/MIME body part)
- 494 Security Agreement Required
5xx - Server Failure Responses
- 500 Server Internal Error
- 501 Not Implemented: The SIP request method is not implemented here
- 502 Bad Gateway
- 503 Service Unavailable
- 504 Server Time-out
- 505 Version Not Supported: The server does not support this version of the SIP protocol
- 513 Message Too Large
- 580 Precondition Failure
6xx - Global Failure Responses
- 600 Busy Everywhere
- 603 Decline
- 604 Does Not Exist Anywhere
- 606 Not Acceptable