SIP 181 Call Is Being Forwarded vs 604 Does Not Exist Anywhere
SIP 181 (Call Is Being Forwarded) is a 1xx Provisional response, while 604 (Does Not Exist Anywhere) 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, 604 means that the server has authoritative information that the user indicated in the Request-URI does not exist anywhere. Unlike 404, this is a definitive, global statement.
説明
A proxy server may send this to indicate that the call is being forwarded to a different set of destinations.
このコードが表示される場合
When the callee has call forwarding enabled and the request is being redirected to another number or device.
解決方法
No action needed. The call is being redirected. If forwarding is unintended, the callee should update their forwarding settings.
説明
The server has authoritative information that the user indicated in the Request-URI does not exist anywhere. Unlike 404, this is a definitive, global statement.
このコードが表示される場合
When the user definitively does not exist on any server in the network. The server has authoritative knowledge, not just local.
解決方法
The user does not exist. Verify the SIP URI or phone number. Unlike 404, retrying on other servers will not help.
主な違い
181 is a 1xx Provisional response, while 604 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 604: The server has authoritative information that the user indicated in the Request-URI does not exist anywhere. Unlike 404, this is a definitive, global statement.
You encounter 181 when when the callee has call forwarding enabled and the request is being redirected to another number or device.
You encounter 604 when when the user definitively does not exist on any server in the network. The server has authoritative knowledge, not just local.
どちらをいつ使うか
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 604 (Does Not Exist Anywhere): The user does not exist. Verify the SIP URI or phone number. Unlike 404, retrying on other servers will not help.