[Asterisk-Dev] SIP channels not cleared

[Kevin P. Fleming]

Chee Foong wrote:

> I have check with the other end's provider. They insists that asterisk
> should be able to accept BYE at any stage in the sip message exchange. Is
> this really true?

No, that is not true. BYE is only allowed for a session that was started 
with an INVITE and accepted with a '200 OK'. If the INVITE has not been 
OK'd, then a 4xx or 5xx failure response must be sent to cancel the 
pending INVITE, not BYE.