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 document provides background information for adminstrators who think they are under attack because they are sending reverse dns queries of the private use addresses and are getting responses back. Security considerations section do point out that sending those queries out from the site might leak information related to the private infrastructure, which might represent a security risk. I do not have any comments related to this document. -- kivinen at iki.fi