SIP 180 Ringing vs 493 Undecipherable
SIP 180 (Ringing) is a 1xx Provisional response, while 493 (Undecipherable) is a 4xx Client Failure response. 180 indicates that the UA receiving the INVITE is trying to alert the user. This response is used to initiate local ringback tone at the caller's end. In contrast, 493 means that the request body was encrypted with S/MIME but the server cannot decrypt it. The server may lack the necessary key or certificate.
Descripción
The UA receiving the INVITE is trying to alert the user. This response is used to initiate local ringback tone at the caller's end.
Cuándo lo verás
During call setup when the callee's phone is ringing. You should hear a ringback tone after receiving this response.
Cómo solucionarlo
No fix needed — the callee's device is ringing. If the call never connects after ringing, check the callee's device or call forwarding settings.
Descripción
The request body was encrypted with S/MIME but the server cannot decrypt it. The server may lack the necessary key or certificate.
Cuándo lo verás
When using S/MIME encryption for SIP message bodies and the recipient does not have the corresponding decryption key.
Cómo solucionarlo
Ensure the recipient has the correct S/MIME certificate and private key. Consider using TLS for transport-layer encryption instead.
Diferencias clave
180 is a 1xx Provisional response, while 493 is a 4xx Client Failure response.
SIP 180: The UA receiving the INVITE is trying to alert the user. This response is used to initiate local ringback tone at the caller's end.
SIP 493: The request body was encrypted with S/MIME but the server cannot decrypt it. The server may lack the necessary key or certificate.
You encounter 180 when during call setup when the callee's phone is ringing. You should hear a ringback tone after receiving this response.
You encounter 493 when when using S/MIME encryption for SIP message bodies and the recipient does not have the corresponding decryption key.
Cuándo usar cada uno
For 180 (Ringing): No fix needed — the callee's device is ringing. If the call never connects after ringing, check the callee's device or call forwarding settings. For 493 (Undecipherable): Ensure the recipient has the correct S/MIME certificate and private key. Consider using TLS for transport-layer encryption instead.