SIP 181 Call Is Being Forwarded vs 607 Unwanted
SIP 181 (Call Is Being Forwarded) is a 1xx Provisional response, while 607 (Unwanted) is a 6xx Global Failure response. 181 indicates that a proxy server may send this to indicate that the call is being forwarded to a different set of destinations. In contrast, 607 means that the called party did not want this call from the calling party. This response is used for robocall and spam call blocking.
Description
A proxy server may send this to indicate that the call is being forwarded to a different set of destinations.
When You See It
When the callee has call forwarding enabled and the request is being redirected to another number or device.
How to Fix
No action needed. The call is being redirected. If forwarding is unintended, the callee should update their forwarding settings.
Description
The called party did not want this call from the calling party. This response is used for robocall and spam call blocking.
When You See It
When the callee's system identifies the call as spam or unwanted. Used in STIR/SHAKEN call verification frameworks.
How to Fix
If you are a legitimate caller being blocked as spam, ensure your STIR/SHAKEN attestation level is 'A' (full attestation). Contact the callee through alternative means.
Key Differences
181 is a 1xx Provisional response, while 607 is a 6xx Global Failure response.
SIP 181: A proxy server may send this to indicate that the call is being forwarded to a different set of destinations.
SIP 607: The called party did not want this call from the calling party. This response is used for robocall and spam call blocking.
You encounter 181 when when the callee has call forwarding enabled and the request is being redirected to another number or device.
You encounter 607 when when the callee's system identifies the call as spam or unwanted. Used in STIR/SHAKEN call verification frameworks.
When to Use Which
For 181 (Call Is Being Forwarded): No action needed. The call is being redirected. If forwarding is unintended, the callee should update their forwarding settings. For 607 (Unwanted): If you are a legitimate caller being blocked as spam, ensure your STIR/SHAKEN attestation level is 'A' (full attestation). Contact the callee through alternative means.