rfc3655.txt

bind 9.3结合mysql数据库


RFC 3655               Redefinition of DNS AD bit          November 2003


   is not advisable to trust these recursive nameservers.  A
   roaming/traveling host SHOULD not use recursive DNS servers offered
   by DHCP when looking up information where security status matters.

   In the latter two cases, the end consumer must also completely trust
   the path to the trusted recursive name servers, or a secure transport
   must be employed to protect the traffic.

   When faced with a situation where there are no satisfactory recursive
   nameservers available, running one locally is RECOMMENDED.  This has
   the advantage that it can be trusted, and the AD bit can still be
   used to allow applications to use stub resolvers.

5.  Security Considerations

   This document redefines a bit in the DNS header.  If a resolver
   trusts the value of the AD bit, it must be sure that the responder is
   using the updated definition, which is any DNS server/resolver
   supporting the DO bit [RFC3225].

   Authoritative servers can be explicitly configured to set the AD bit
   on answers without doing cryptographic checks.  This behavior MUST be
   off by default.  The only affected resolvers are those that directly
   query and trust the authoritative server, and this functionality
   SHOULD only be used on servers that act both as authoritative and
   recursive name servers.

   Resolvers (full or stub) that blindly trust the AD bit without
   knowing the security policy of the server generating the answer can
   not be considered security aware.

   A resolver MUST NOT blindly trust the AD bit unless it communicates
   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 recursive name server.

6.  IANA Considerations

   None.

7.  Internationalization Considerations

   None.  This document does not change any textual data in any
   protocol.







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RFC 3655               Redefinition of DNS AD bit          November 2003


8.  Intellectual Property Rights Notice

   The IETF takes no position regarding the validity or scope of any
   intellectual property or other rights that might be claimed to
   pertain to the implementation or use of the technology described in
   this document or the extent to which any license under such rights
   might or might not be available; neither does it represent that it
   has made any effort to identify any such rights.  Information on the
   IETF's procedures with respect to rights in standards-track and
   standards-related documentation can be found in BCP-11.  Copies of
   claims of rights made available for publication and any assurances of
   licenses to be made available, or the result of an attempt made to
   obtain a general license or permission for the use of such
   proprietary rights by implementors or users of this specification can
   be obtained from the IETF Secretariat.

   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights which may cover technology that may be required to practice
   this standard.  Please address the information to the IETF Executive
   Director.

9.  Acknowledgments

   The following people have provided input on this document: Robert
   Elz, Andreas Gustafsson, Bob Halley, Steven Jacob, Erik Nordmark,
   Edward Lewis, Jakob Schlyter, Roy Arends, Ted Lindgreen.

10.  Normative References

   [RFC1035] Mockapetris, P., "Domain Names - Implementation and
             Specification", STD 13, RFC 1035, November 1987.

   [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
             Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2535] Eastlake, D., "Domain Name System Security Extensions", RFC
             2535, March 1999.

   [RFC2845] Vixie, P., Gudmundsson, O., Eastlake 3rd, D. and B.
             Wellington, "Secret Key Transaction Authentication for DNS
             (TSIG)", RFC 2845, May 2000.

   [RFC2931] Eastlake, D., "DNS Request and Transaction Signatures
             (SIG(0))", RFC 2931, September 2000.

   [RFC3225] Conrad, D., "Indicating Resolver Support of DNSSEC", RFC
             3225, December 2001.



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RFC 3655               Redefinition of DNS AD bit          November 2003


11.  Authors' Addresses

   Brian Wellington
   Nominum Inc.
   2385 Bay Road
   Redwood City, CA, 94063
   USA

   EMail: [e-mail]


   Olafur Gudmundsson
   3821 Village Park Drive
   Chevy Chase, MD, 20815
   USA

   EMail: [e-mail]


































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RFC 3655               Redefinition of DNS AD bit          November 2003


12.  Full Copyright Statement

   Copyright (C) The Internet Society (2003).  All Rights Reserved.

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph are
   included on all such copies and derivative works.  However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
   Internet organizations, except as needed for the purpose of
   developing Internet standards in which case the procedures for
   copyrights defined in the Internet Standards process must be
   followed, or as required to translate it into languages other than
   English.

   The limited permissions granted above are perpetual and will not be
   revoked by the Internet Society or its successors or assignees.

   This document and the information contained herein is provided on an
   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Acknowledgement

   Funding for the RFC Editor function is currently provided by the
   Internet Society.



















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