SIP 100 Trying vs 405 Method Not Allowed
SIP 100 (Trying) is a 1xx Provisional response, while 405 (Method Not Allowed) is a 4xx Client Failure response. 100 indicates that the request has been received by the next-hop server and an unspecified action is being taken to process it. The UAC should expect additional responses. In contrast, 405 means that the method specified in the Request-Line is not allowed for the address identified by the Request-URI.
Descripción
The request has been received by the next-hop server and an unspecified action is being taken to process it. The UAC should expect additional responses.
Cuándo lo verás
Immediately after sending an INVITE. The proxy has received the call and is searching for the callee. This is the SIP equivalent of a dial tone.
Cómo solucionarlo
No fix needed — this is normal call setup behavior. If stuck on 100 Trying for too long, check network connectivity and proxy configuration.
Descripción
The method specified in the Request-Line is not allowed for the address identified by the Request-URI.
Cuándo lo verás
When sending a SIP method (e.g., MESSAGE, PUBLISH) that the server does not support for the target URI.
Cómo solucionarlo
Check the Allow header in the response to see which methods are supported. Use a supported method instead.
Diferencias clave
100 is a 1xx Provisional response, while 405 is a 4xx Client Failure response.
SIP 100: The request has been received by the next-hop server and an unspecified action is being taken to process it. The UAC should expect additional responses.
SIP 405: The method specified in the Request-Line is not allowed for the address identified by the Request-URI.
You encounter 100 when immediately after sending an INVITE. The proxy has received the call and is searching for the callee. This is the SIP equivalent of a dial tone.
You encounter 405 when when sending a SIP method (e.g., MESSAGE, PUBLISH) that the server does not support for the target URI.
Cuándo usar cada uno
For 100 (Trying): No fix needed — this is normal call setup behavior. If stuck on 100 Trying for too long, check network connectivity and proxy configuration. For 405 (Method Not Allowed): Check the Allow header in the response to see which methods are supported. Use a supported method instead.