RFC 3261 does not allow the To/From uri matching values to change within a dialog. RFC 4916 provides the ability to alter To/From uri matching values; however it requires the support/use of option-tag “from-change”. Except per RFC 4916, I’m not aware of an RFC which has officially deprecated the To/From rules mandated by RFC 3261 section 12.2.1.1.
RFC 3261 section 12.2.1.1: "A request within a dialog is constructed by using many of the components of the state stored as part of the dialog. The URI in the To field of the request MUST be set to the remote URI from the dialog state. The tag in the To header field of the request MUST be set to the remote tag of the dialog ID. The From URI of the request MUST be set to the local URI from the dialog state. The tag in the From header field of the request MUST be set to the local tag of the dialog ID." _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
