SIP 202 Accepted vs 405 Method Not Allowed
SIP 202 (Accepted) is a 2xx Success response, while 405 (Method Not Allowed) is a 4xx Client Failure response. 202 indicates that the request has been accepted for processing but the processing has not been completed. Used primarily for REFER requests. In contrast, 405 means that the method specified in the Request-Line is not allowed for the address identified by the Request-URI.
Description
The request has been accepted for processing but the processing has not been completed. Used primarily for REFER requests.
When You See It
After sending a REFER request for call transfer. The transfer target acknowledges receipt but hasn't completed the transfer yet.
How to Fix
Wait for a NOTIFY to learn the outcome of the referred action. If no NOTIFY arrives, check subscription state and network connectivity.
Description
The method specified in the Request-Line is not allowed for the address identified by the Request-URI.
When You See It
When sending a SIP method (e.g., MESSAGE, PUBLISH) that the server does not support for the target URI.
How to Fix
Check the Allow header in the response to see which methods are supported. Use a supported method instead.
Key Differences
202 is a 2xx Success response, while 405 is a 4xx Client Failure response.
SIP 202: The request has been accepted for processing but the processing has not been completed. Used primarily for REFER requests.
SIP 405: The method specified in the Request-Line is not allowed for the address identified by the Request-URI.
You encounter 202 when after sending a REFER request for call transfer. The transfer target acknowledges receipt but hasn't completed the transfer yet.
You encounter 405 when when sending a SIP method (e.g., MESSAGE, PUBLISH) that the server does not support for the target URI.
When to Use Which
For 202 (Accepted): Wait for a NOTIFY to learn the outcome of the referred action. If no NOTIFY arrives, check subscription state and network connectivity. For 405 (Method Not Allowed): Check the Allow header in the response to see which methods are supported. Use a supported method instead.