I'm almost certain that what you want is the mechanism Olle described, that if the registrar supports the feature, then it it sends "Supported: xxx" in the response to the REGISTER, and the CPE (UAC) determines whether to activate the feature based on the presence or absence of "xxx".
It might help if you describe what the feature is. Depending on the feature, there may be better places in the logic to decide whether it is active that at the moment of registration. Dale _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors