SIP 183 Session Progress vs 407 Proxy Authentication Required
SIP 183 (Session Progress) is a 1xx Provisional response, while 407 (Proxy Authentication Required) 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, 407 means that the client must first authenticate with the proxy. The proxy returns a Proxy-Authenticate header with a challenge.
説明
Used to convey information about the progress of the call that is not otherwise classified. Often carries early media (ringback tones, announcements) via SDP.
このコードが表示される場合
During call setup, especially in PSTN interworking scenarios. The response may contain SDP for early media like custom ringback tones or IVR prompts.
解決方法
No fix needed — this is informational. If early media is not playing, check codec negotiation and SDP handling in your UA.
説明
The client must first authenticate with the proxy. The proxy returns a Proxy-Authenticate header with a challenge.
このコードが表示される場合
When a SIP proxy requires authentication before forwarding the request. Similar to 401 but for proxy servers.
解決方法
Resend the request with a Proxy-Authorization header containing valid credentials for the proxy.
主な違い
183 is a 1xx Provisional response, while 407 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 407: The client must first authenticate with the proxy. The proxy returns a Proxy-Authenticate header with a challenge.
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 407 when when a SIP proxy requires authentication before forwarding the request. Similar to 401 but for proxy servers.
どちらをいつ使うか
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 407 (Proxy Authentication Required): Resend the request with a Proxy-Authorization header containing valid credentials for the proxy.