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. This draft suggests two new DNS RRtypes that could encode IEEE EUI-48 and EUI-64 layer-2 addresses. There is at least one known use case of a Canadian required reverse DNS mapping of IP addresses to MAC addresses. The draft is simple and straight forward and follows the usual procedure for requesting a new RRtype. Security concern. You might want to mention that publication of the EUI's could facilitate MAC cloning. This isn't original to me. I followed the reference to the Canadian CRTC decision NTRE038D and looked at the various company "contributions" that led to that decision. One contribution from Clearcable (NTCO0362, see http://www.crtc.gc.ca/public/cisc/nt/NTCO0362.pdf ) speaks of the risk that publication of EUI addresses in the global reverse DNS would facilitate the theft of service that arises from cloning the MAC address of a valid subscriber. DOCSIS modem MAC cloning does seem to be a known problem and concern, so perhaps this should be mentioned. The draft recommends restricting access to zones containing EUI64 addresses to limit the privacy exposure. This is similar to the recommendation in the NTRE038D to use a split-view reverse DNS service. The draft's recommendation would also limit the exposure of valid EUI-64 addresses to MAC cloners, so I don't think you need to describe additional countermeasures. Nits and even more anal comments: Section 9 says "with the Global bit zero". I presume you mean the next-to-least-significant-bit in the first octet. RFC 5342 calls this bit the "Local bit" and the "Local/Global bit". RFC4291 calls this the "universal/local" bit. The IEEE 802 standard talks about "universal" and "local" without actually naming the bit, but lots of online documentation says "universal/local" and "U/L". So you and the RFC Editor can decide what term to use. IMHO: Continuing to call it the "Global bit" is my least favorite choice. Consistency with RFC5342 or RFC4291 would be preferable. Section 9 says: Publication of EUI-48 or EUI-64 addresses in the global DNS may result in privacy issues in the form of unique trackable identities. The privacy concern arises not just from the uniqueness of the EUI but from the fact that it is a more permanent identifier than the IP address associated with the subscriber (as the next paragraph notes). So "in the form of unique, permanent trackable identities" is probably more accurate. Similarly in the next paragraph "EUI-64 addresses normally provide a unique identifier" - the point is that the IP address "typically change over time" so "provide a unique permanent identifier" is what you mean. I think. The details of the IEEE references are incomplete. I might have recommended copying the references in RFC5342 but those references look to be out of date. I did find "Guidelines for 64-bit Global Identifier (EUI-64)" http://standards.ieee.org/develop/regauth/tut/eui64.pdf . The URL shown in RFC5342 for [EUI-64] redirects to that URL. --Sandy