Was bedeuten die SIP-Fehlercodes 403, 404 u.a. ?

2xx Successful
200 OK   

3xx Redirection
300 Multiple Choices   
301 Moved Permanently   
302 Moved Temporarily   
305 Use Proxy   
380 Alternative Service   

4xx Request Failure
400 Bad Request
401 Unauthorized
402 Payment Required
403 Forbidden
404 Not Found
405 Method Not Allowed
406 Not Acceptable
407 Proxy Authentication Required
408 Request Timeout
409 Conflict
410 Gone
411 Length Required
413 Request Entity Too Large
414 Request-URI Too Long
415 Unsupported Media Type
420 Bad Extension
480 Temporarily Unavailable
481 Call Leg/Transaction Does Not Exist
482 Loop Detected
483 Too Many Hops
484 Address Incomplete
485 Ambiguous
486 Busy Here

5xx Server Failure
500 Server Internal Error
501 Not Implemented
502 Bad Gateway
503 Service Unavailable
504 Gateway Time-out
505 Version Not Supported

6xx Global Failures
600 Busy Everywhere
603 Decline
604 Does Not Exist Anywhere
606 Not Acceptable

Quelle: RFC 2543