SIP 183 Session Progress vs 438 Invalid Identity Header
SIP 183 (Session Progress) is a 1xx Provisional response, while 438 (Invalid Identity Header) is a 4xx Client Failure response. 183 indicates that used to convey information about the progress of the call that is not otherwise classified. Often carries early media (ringback tones, announcements) via SDP. In contrast, 438 means that the server obtained the certificate from the Identity-Info header but the signature in the Identity header is invalid.
विवरण
Used to convey information about the progress of the call that is not otherwise classified. Often carries early media (ringback tones, announcements) via SDP.
जब आप इसे देखें
During call setup, especially in PSTN interworking scenarios. The response may contain SDP for early media like custom ringback tones or IVR prompts.
कैसे ठीक करें
No fix needed — this is informational. If early media is not playing, check codec negotiation and SDP handling in your UA.
विवरण
The server obtained the certificate from the Identity-Info header but the signature in the Identity header is invalid.
जब आप इसे देखें
When the cryptographic signature in the Identity header does not match the message content, indicating possible tampering.
कैसे ठीक करें
Regenerate the Identity header with a correct signature. Ensure no intermediary is modifying signed headers after signing.
मुख्य अंतर
183 is a 1xx Provisional response, while 438 is a 4xx Client Failure response.
SIP 183: Used to convey information about the progress of the call that is not otherwise classified. Often carries early media (ringback tones, announcements) via SDP.
SIP 438: The server obtained the certificate from the Identity-Info header but the signature in the Identity header is invalid.
You encounter 183 when during call setup, especially in PSTN interworking scenarios. The response may contain SDP for early media like custom ringback tones or IVR prompts.
You encounter 438 when when the cryptographic signature in the Identity header does not match the message content, indicating possible tampering.
कब किसका उपयोग करें
For 183 (Session Progress): No fix needed — this is informational. If early media is not playing, check codec negotiation and SDP handling in your UA. For 438 (Invalid Identity Header): Regenerate the Identity header with a correct signature. Ensure no intermediary is modifying signed headers after signing.