SIP 181 Call Is Being Forwarded vs 420 Bad Extension
SIP 181 (Call Is Being Forwarded) is a 1xx Provisional response, while 420 (Bad Extension) is a 4xx Client 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, 420 means that the server did not understand the protocol extension specified in a Require or Proxy-Require header. The Unsupported header lists the unknown extensions.
Mô tả
A proxy server may send this to indicate that the call is being forwarded to a different set of destinations.
Khi bạn thấy mã này
When the callee has call forwarding enabled and the request is being redirected to another number or device.
Cách khắc phục
No action needed. The call is being redirected. If forwarding is unintended, the callee should update their forwarding settings.
Mô tả
The server did not understand the protocol extension specified in a Require or Proxy-Require header. The Unsupported header lists the unknown extensions.
Khi bạn thấy mã này
When the request includes a Require header with SIP extensions that the server does not support.
Cách khắc phục
Check the Unsupported header in the response. Remove the unsupported extension from the Require header or make it optional via Supported.
Sự khác biệt chính
181 is a 1xx Provisional response, while 420 is a 4xx Client 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 420: The server did not understand the protocol extension specified in a Require or Proxy-Require header. The Unsupported header lists the unknown extensions.
You encounter 181 when when the callee has call forwarding enabled and the request is being redirected to another number or device.
You encounter 420 when when the request includes a Require header with SIP extensions that the server does not support.
Khi nào dùng cái nào
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 420 (Bad Extension): Check the Unsupported header in the response. Remove the unsupported extension from the Require header or make it optional via Supported.