SIP 200 OK vs 420 Bad Extension
SIP 200 (OK) is a 2xx Success response, while 420 (Bad Extension) is a 4xx Client Failure response. 200 indicates that the request has succeeded. For INVITE, the call has been answered. For other methods, the action has been completed successfully. 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.
Descripción
The request has succeeded. For INVITE, the call has been answered. For other methods, the action has been completed successfully.
Cuándo lo verás
When a call is answered (INVITE 200 OK), a registration succeeds (REGISTER 200 OK), or a subscription is accepted (SUBSCRIBE 200 OK).
Cómo solucionarlo
No fix needed — this is a success response. The caller should send an ACK to complete the three-way handshake for INVITE transactions.
Descripción
The server did not understand the protocol extension specified in a Require or Proxy-Require header. The Unsupported header lists the unknown extensions.
Cuándo lo verás
When the request includes a Require header with SIP extensions that the server does not support.
Cómo solucionarlo
Check the Unsupported header in the response. Remove the unsupported extension from the Require header or make it optional via Supported.
Diferencias clave
200 is a 2xx Success response, while 420 is a 4xx Client Failure response.
SIP 200: The request has succeeded. For INVITE, the call has been answered. For other methods, the action has been completed successfully.
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 200 when when a call is answered (INVITE 200 OK), a registration succeeds (REGISTER 200 OK), or a subscription is accepted (SUBSCRIBE 200 OK).
You encounter 420 when when the request includes a Require header with SIP extensions that the server does not support.
Cuándo usar cada uno
For 200 (OK): No fix needed — this is a success response. The caller should send an ACK to complete the three-way handshake for INVITE transactions. 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.