I have reviewed this document as part of the security directorate's ongoing effort to review all IETF documents being processed by the IESG. These comments were written primarily for the benefit of the security area directors. Document editors and WG chairs should treat these comments just like any other last call comments. The summary of the review is that this document is has one substantial issue plus a formatting nit: the author names are running into the title. Perhaps this can be fixed The substantial comment is that the interaction of privacy addresses with giving each subscriber a unique IPv6 address prefix space is not discussed in this document at all. This seems like a security issue that should be addressed as it reduces privacy compared to a shared prefix for all users. (Or maybe I am completely wrong: I do not know IPv6 in great detail). At minimum it should be discussed in the security considerations section, even if explicitly dismissed. Sincerely, Watson