Redefinition of DNS Authenticated Data (AD) bit
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From: The IESG <email@example.com> To: IETF-Announce <firstname.lastname@example.org> Cc: Internet Architecture Board <email@example.com>, RFC Editor <firstname.lastname@example.org>, dnsext mailing list <email@example.com>, dnsext chair <firstname.lastname@example.org> Subject: Protocol Action: 'Redefinition of DNS AD bit' to Proposed Standard The IESG has approved the following document: - 'Redefinition of DNS AD bit ' <draft-ietf-dnsext-ad-is-secure-07.txt> as a Proposed Standard This document is the product of the DNS Extensions Working Group. The IESG contact persons are Erik Nordmark and Mark Townsley. A URL of this Internet-Draft is: http://www.ietf.org/internet-drafts/draft-ietf-dnsext-ad-is-secure-07.txt
Technical Summary Based on implementation experience, the current definition of the AD bit in the DNS header is not useful. This draft changes the specification so that the AD bit is only set on answers where signatures have been cryptographically verified or the server is authoritative for the data and is allowed to set the bit by policy. Working Group Summary There was some dissent expressed by one person whether the AD bit carries any semantics which can not be inferred from the replies which the stub resolver receives. Protocol Quality The specification has been reviewed for the IESG by Erik Nordmark. RFC-editor notes: Please add the standard IPR section to the document. Before the last paragraph in section 4 add this paragraph: In the latter two cases, the end consumer must also completely trust the network path to the trusted resolvers or a secure transport is employed to protect the traffic. Add this paragraph to the end of section 2.2: Note that having the AD bit clear on an authoritative answer is normal and expected behavior. The draft also has an odd "MUST" in section 2.2.1: Organisations that require that all DNS responses contain cryptographically verified data MUST separate the functions of authoritative and recursive servers, as authoritative servers are not required to validate local secure data. This introduces a new concept "local secure data", w/o defining it. Replace that paragraph with: Organisations which require that all DNS responses contain cryptographically verified data will need to separate the authoritative name server and signature verification functions, since name servers are not required to validate signatures of data for which they are authoritative. Add this paragraph at the end of the security considerations section: A resolver MUST NOT blindly trust the AD bit unless it communicates with the full function resolver over a secure transport mechanism, such as IPsec, or using message authentication such as TSIG [RFC2845] or SIG(0) [RFC2931]. In addition, the resolver must have been explicitly configured to trust this resolver.