SIP 200 OK vs 439 First Hop Lacks Outbound Support
SIP 200 (OK) is a 2xx Success response, while 439 (First Hop Lacks Outbound Support) 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, 439 means that the first outbound proxy does not support the SIP outbound mechanism (RFC 5626) that the UA is trying to use.
Описание
The request has succeeded. For INVITE, the call has been answered. For other methods, the action has been completed successfully.
Когда вы это видите
When a call is answered (INVITE 200 OK), a registration succeeds (REGISTER 200 OK), or a subscription is accepted (SUBSCRIBE 200 OK).
Как исправить
No fix needed — this is a success response. The caller should send an ACK to complete the three-way handshake for INVITE transactions.
Описание
The first outbound proxy does not support the SIP outbound mechanism (RFC 5626) that the UA is trying to use.
Когда вы это видите
When a UA configured for SIP outbound connects to a proxy that doesn't support the outbound option-tag.
Как исправить
Upgrade the outbound proxy to support RFC 5626, or configure the UA to not require outbound support.
Ключевые различия
200 is a 2xx Success response, while 439 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 439: The first outbound proxy does not support the SIP outbound mechanism (RFC 5626) that the UA is trying to use.
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 439 when when a UA configured for SIP outbound connects to a proxy that doesn't support the outbound option-tag.
Когда что использовать
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 439 (First Hop Lacks Outbound Support): Upgrade the outbound proxy to support RFC 5626, or configure the UA to not require outbound support.