Network Working Group M. Andrews Internet-Draft ISC Intended status: Best Current March 2, 2007 Practice Expires:
December 17, 2006 June 15, 2006September 3, 2007 Locally-served DNS Zones draft-ietf-dnsop-default-local-zones-00draft-ietf-dnsop-default-local-zones-01 Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on December 17, 2006.September 3, 2007. Copyright Notice Copyright (C) The Internet Society (2006).IETF Trust (2007). Abstract Practice has shown that there are a number of DNS zones all iterative resolvers and recursive nameservers should, unless configured otherwise, automatically serve. RFC 4193 already specifies that this should occur for D.F.IP6.ARPA. This document extends the practice to cover the IN-ADDR.ARPA zones for RFC 1918 address space and other well known zones with similar usage constraints. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Reserved Words . . . . . . . . . . . . . . . . . . . . . . 3 2. Effects on sites using RFC 1918 addresses. . . . . . . . . . . 3 3. Changes to Iterative Resolver Behaviour. . . . . . . . . . . . .4 4. Lists Of Zones Covered . . . . . . . . . . . . . . . . . . . . 45 4.1. RFC 1918 Zones . . . . . . . . . . . . . . . . . . . . . . 45 4.2. RFC 3330 Zones . . . . . . . . . . . . . . . . . . . . . . 5 4.3. Local IPv6 Unicast Addresses . . . . . . . . . . . . . . . 56 4.4. IPv6 Locally Assigned Local Addresses . . . . . . . . . . 56 4.5. IPv6 Link Local Addresses . . . . . . . . . . . . . . . . 56 5. Zones that are Out-Of-Scope . . . . . . . . . . . . . . . . . 56 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 67 7. Security Considerations . . . . . . . . . . . . . . . . . . . 67 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 78 9.1. Normative References . . . . . . . . . . . . . . . . . . . 78 9.2. Informative References . . . . . . . . . . . . . . . . . . 78 Appendix A. Change History [To Be Removed on Publication] . . . . 89 A.1. draft-ietf-dnsop-default-local-zones-00.txtdraft-ietf-dnsop-default-local-zones-01.txt . . . . . . . 89 A.2. draft-andrews-full-service-resolvers-03.txtdraft-ietf-dnsop-default-local-zones-00.txt . . . . . . . 89 A.3. draft-andrews-full-service-resolvers-03.txt . . . . . . . 9 A.4. draft-andrews-full-service-resolvers-02.txt . . . . . . . 89 Appendix B. Proposed Status [To Be Removed on Publication] . . . 89 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 9 Intellectual Property and Copyright Statements . . . . . . . . . . 10 1. Introduction Practice has shown that there are a number of DNS [RFC 1034] [RFC 1035] zones all iterative resolvers and recursive nameservers should, unless configured otherwise, automatically serve. These zones include, but are not limited to, the IN-ADDR.ARPA zones for the address space allocated by [RFC 1918] and the IP6.ARPA zones for locally assigned local IPv6 addresses, [RFC 4193]. This recommendation is made because data has shown that significant leakage of queries for these name spaces is occurring, despite instructions to restrict them, and because sacrificial name servers have been deployed to protect the immediate parent name servers for these zones from excessive, unintentional, query load [AS112]. There is every expectation that the query load will continue to increase unless steps are taken as outlined here. Additionally, queries from clients behind badly configured firewalls that allow outgoing queries but drop responses for these name spaces also puts a significant load on the root servers. They also cause operational load for the root server operators as they have to reply to queries about why the root servers are "attacking" these clients. Changing the default configuration will address all these issues for the zones below.listed below in Section 4. [RFC 4193] already recommends that queries for D.F.IP6.ARPA be handled locally. This document extends the recommendation to cover the IN-ADDR.ARPA zones for [RFC 1918] and other well known IN- ADDR.ARPA and IP6.ARPA zones for which queries should not appear on the public Internet. It is hoped that by doing this the number of sacrificial servers [AS112] will not have to be increased and may in time be reduced. It should also help DNS responsiveness for sites which are using [RFC 1918] addresses but are misconfigured.do not follow the last paragraph in section 3 of [RFC 1918]. 1.1. Reserved Words The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC 2119]. 2. Effects on sites using RFC 1918 addresses. SitesFor most sites using [RFC 1918] addresses shouldaddresses, the changes here will have little or no detrimental effect. If the site does not already have the reverse tree populated the only effect will be serving thesethat the answers are generated locally rather than remotely. For sites that do have the reverse tree populated, most will either have a local copy of the zones or will be forwarding the queries internally, without referring themto public nameservers onwhich have local copies of the Internet.zone. In either case the local resolver has a pre-existing configuration for the namespace and won't add the automatic zone. The main impact will be felt onat sites that make use of recursiondelegation for reverse lookups for [RFC 1918] addresses and have populated these zones. Typically, such sites will be fully disconnected from the Internet and have their own root servers for their own non-Internet DNS tree or make use of local delegation overrides (otherwise known as "forwarding") to reach the private servers for these reverse zones.tree. These sites will need to override the default configuration proposedexpressed in this draftdocument to allow resolution to continue. Other sites that use [RFC 1918] addresses and either have local copies of the reverse zones or don't have reverse zones configured should see no difference other than the name error appearing to come from a different source.3. Changes to Iterative Resolver Behaviour. Unless configured otherwise, aan iterative resolver will now return name errors (RCODE=3) for queries within the lists of zones covered below.below, with the obvious exception of queries for the zone name itself where SOA, NS and "no data" responses will be returned as appropriate to the query type. One common way to do this is to serve empty (SOA and NS only) zones. A serverimplementation doing this MUST provide a mechanism to disable this new behaviour, preferably on a zone by zone basis. If using empty zones one should notSHOULD NOT use the same NS and SOA records as used on the public Internet servers as that will make it harder to detect leakage fromto the public Internet servers. This document recommends that the NS record defaultdefaults to the name of the zone and the SOA MNAME defaultdefaults to the name of the zone.only NS RR's target. The SOA RNAME should default to ".". Implementations SHOULD provide a mechanism to set these values. No address records need to be provided for the name server. Below is a example of a generic empty zone in master file format. It will produce a negative cache ttl of 3 hours. @ 10800 IN SOA @ . 1 3600 1200 604800 10800 @ 10800 IN NS @ 4. Lists Of Zones CoveredThe lists below are expectedSOA RR is needed to seed a IANA registry. 4.1.support negative caching [RFC 2308] of name error responses and to point clients to the primary master for DNS dynamic updates. SOA values of particular importance are the MNAME, the SOA RR's TTL and the negTTL value. Both TTL values SHOULD match. The rest of the SOA timer values may be chosen arbitrarily since it they are not intended to control any zone transfer activity. The NS RR is needed as some UPDATE clients use NS queries to discover they zone to be updated. Having no address records for the name server should abort UPDATE processing in the client 4. Lists Of Zones Covered The lists below are expected to seed a IANA registry. 4.1. RFC 1918 Zones 10.IN-ADDR.ARPA 16.172.IN-ADDR.ARPA 17.172.IN-ADDR.ARPA 18.172.IN-ADDR.ARPA 19.172.IN-ADDR.ARPA 20.172.IN-ADDR.ARPA 21.172.IN-ADDR.ARPA 22.172.IN-ADDR.ARPA 23.172.IN-ADDR.ARPA 24.172.IN-ADDR.ARPA 25.172.IN-ADDR.ARPA 26.172.IN-ADDR.ARPA 27.172.IN-ADDR.ARPA 28.172.IN-ADDR.ARPA 29.172.IN-ADDR.ARPA 30.172.IN-ADDR.ARPA 31.172.IN-ADDR.ARPA 168.192.IN-ADDR.ARPA 4.2. RFC 3330 Zones See [RFC 3330]. 0.IN-ADDR.ARPA /* IPv4 "THIS" NETWORK */ 127.IN-ADDR.ARPA /* IPv4 LOOP-BACK NETWORK */ 254.169.IN-ADDR.ARPA /* IPv4 LINK LOCAL */ 2.0.192.IN-ADDR.ARPA /* IPv4 TEST NET */ 255.255.255.255.IN-ADDR.ARPA /* IPv4 BROADCAST */ 4.3. Local IPv6 Unicast Addresses See [RFC 4291], sections 2.4, 2.5.2 and 2.5.3. 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.IP 6.ARPA 18.104.22.168.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.IP 6.ARPA 4.4. IPv6 Locally Assigned Local Addresses See [RFC 4193]. D.F.IP6.ARPA 4.5. IPv6 Link Local Addresses See [RFC 4291], sections 2.4 and 2.5.6. 8.E.F.IP6.ARPA 9.E.F.IP6.ARPA A.E.F.IP6.ARPA B.E.F.IP6.ARPA 5. Zones that are Out-Of-Scope IPv6 site-local addressesaddresses, [RFC 4291] sections 2.4 and 2.57, and IPv6 Globally Assigned Local [RFC 4193] addresses are not covered here. It is expected that IPv6 site-local addresses will be self correcting as IPv6 implementations remove support for site-local addresses however,addresses. However, sacrificial servers for C.E.F.IP6.ARPA to F.E.F.IP6.ARPA may still need to be deployed in the short term if the traffic becomes excessive. For IPv6 Globally Assigned Local addresses [RFC 4291] there has been no decision made about whether the registries will provide delegations in this space or not. If they don'tdon't, then C.F.IP6.ARPA will need to be added to the list above. If they dodo, then registries will need to take steps to ensure that name servers are provided for these addresses. This document is also ignoring the IP6.INT counterpart for the IP6.ARPA addresses above.IP6.INT. IP6.INT is in the process of beinghas been wound up with clients already not querying for this suffix.only legacy resolvers now generating reverse queries under IP6.INT. This document has also deliberately ignored zonesnames immediately under the root. The author believes other methods wouldWhile there is a subset of queries to the roots which could be more applicable for dealing withaddressed using the excess / bogustechniques described here (e.g. .local and IPv4 addresses) there is also a vast amount of traffic these generate.that requires a different strategy (e.g. lookups for unqualied hostnames, IPv6 addresses). 6. IANA Considerations This document recommends that IANA establish a registry of zones which require this default behaviour, the initial contents of which are above.in Section 4. More zones are expected to be added, and possibly deleted from this registry over time. Name server implementors are encouraged to check this registry and adjust their implementations to reflect changes therein. This registry can be amended through IESG reviewed RFC publication."IETF Consensus" as per [RFC 2434] or IETF Review in 2434bis. IANA should co-ordinate with the RIRs and ICANN to ensure the DNSSEC deployment in the reverse trees that these zone are delegated in a unsecure manner as per Security Considerations. 7. Security Considerations During the initial deployment phase, particularly where [RFC 1918] addresses are in use, there may be some clients that unexpectedly receive a name error rather than a PTR record. This may cause some service disruption until full service resolvers have been re- configured. When DNSSEC is deployed within the IN-ADDR.ARPA and IP6.ARPA namespaces, the zones listed above will need to be delegated as insecure delegations. This will allow DNSSEC validation to succeed for queries in these spaces despite not being answered from the delegated servers. It is recommended that sites actively using these namespaces secure them using DNSSEC [RFC 4035] by publishing and using DNSSEC trust anchors. This is good just on general principles. Itwill alsoprotect the clients from accidental leakage of unsigned answers from the Internet which will be unsigned.Internet. 8. Acknowledgements This work was supported by the US National Science Foundation (research grant SCI-0427144) and DNS-OARC. 9. References 9.1. Normative References [RFC 1034] Mockapetris, P., "DOMAIN NAMES - CONCEPTS AND FACILITIES", RFC 1034, STD 13, November 1987. [RFC 1035] Mockapetris, P., "DOMAIN NAMES - IMPLEMENTATION AND SPECIFICATION", RFC 1035, STD 13, November 1987. [RFC 1918] Rekhter, Y., Moskowitz, B., Karrenberg, D., de Groot, G., and E. Lear, "Address Allocation for Private Internets", RFC 1918, February 1996. [RFC 2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC 2308] Andrews, M., "Negative Caching of DNS Queries (DNS NCACHE)", RFC 2398, March 1998. [RFC 2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 2434, October 1998. [RFC 3330] "Special-Use IPv4 Addresses", RFC 3330, September 2002. [RFC 4035] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "Protocol Modifications for the DNS Security Extensions", RFC 4035, March 2005. [RFC 4291] Hinden, R. and S. Deering, "IP Version 6 Addressing Architecture", RFC 4291, February 2006. 9.2. Informative References [AS112] "AS112 Project", <http://as112.net/>. [RFC 4193] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast Addresses", RFC 4193, October 2005. Appendix A. Change History [To Be Removed on Publication] A.1. draft-ietf-dnsop-default-local-zones-01.txt Revised impact description. Updated to reflect change in IP6.INT status. A.2. draft-ietf-dnsop-default-local-zones-00.txt Adopted by DNSOP. "Author's Note" re-titled "Zones that are Out-Of-Scope" Add note that these zone are expected to seed the IANA registry. Title changed. A.2.A.3. draft-andrews-full-service-resolvers-03.txt Added "Proposed Status". A.3.A.4. draft-andrews-full-service-resolvers-02.txt Added 0.IN-ADDR.ARPA. Appendix B. Proposed Status [To Be Removed on Publication] This Internet-Draft is being submitted for eventual publication as an RFC with a proposed status of Best Current Practice. Author's Address Mark P. Andrews Internet Systems Consortium 950 Charter Street Redwood City, CA 94063 US Email: Mark_Andrews@isc.org Full Copyright Statement Copyright (C) The IETF Trust (2007). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM 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. Intellectual Property StatementThe IETF takes no position regarding the validity or scope of any Intellectual Property Rights 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; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat 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 implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at email@example.com. Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM 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. Copyright Statement Copyright (C) The Internet Society (2006). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights.Acknowledgment Funding for the RFC Editor function is currentlyprovided by the Internet Society. Download this as a fileIETF Administrative Support Activity (IASA).