DNSOP Working Group Levon Esibov INTERNET-DRAFT Stuart Kwan Category: Best Current Practice Microsoft February 22, 2001 Suppressing DNS queries to the names under reserved top level domains Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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 document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (2001). All Rights Reserved. Abstract A set of top level domains was recently reserved for testing and documentation purposes. Currently, there is work in progress to reserve a top level domain to be used only in private networks. It is inevitable that some DNS queries for the names under these domains will leak to the Internet. To prevent the load of such ineffectual queries on the root servers, special configuration of the public DNS servers is recommended in this document. Esibov & Kwan BCP [Page 1] INTERNET-DRAFT Suppressing DNS queries 22 February 2001 1. Introduction RFC 2606 [RFC2606] specifies a set of top level domains reserved for testing and documentation purposes. Currently, there is work in progress to reserve a top level domain to be used only in private networks [PRI]. Queries for any names under these domains are not intended to be resolved on the Internet. It is inevitable that some DNS queries for the names under these domains will leak to the Internet. To prevent the load of such ineffectual queries on the root DNS servers, special configuration of the public DNS servers is recommended in this document. In this document, the key words "MAY", "MUST, "MUST NOT", "optional", "recommended", "SHOULD", and "SHOULD NOT", are to be interpreted as described in [RFC2119]. 2. Recommended configuration of the DNS servers. To prevent DNS queries for names under the reserved domains (domains with names not intended to be resolved on the Internet) from being sent to the root DNS servers, it is recommended that DNS servers on the Internet are configured as primary for all of the zones corresponding to the reserved domains. These zones do not need to contain any data except the required SOA and NS records at the top of the zone. List of such zones includes .test .example .invalid .localhost .pri (not reserved yet) Such a list may grow with the introduction of new reserved domains that are not intended for use on the Internet. 3. Example When a query for any record set for a name host.example is received by any Internet DNS server, the DNS server will respond to such a query with a NXDOMAIN response, thus suppressing unnecessary recursive resolution and saving network resources, the resources on the DNS server itself, and the resources on the root servers. Esibov & Kwan BCP [Page 2] INTERNET-DRAFT Suppressing DNS queries 22 February 2001 4. IANA Considerations IANA's consideration is not required. The list of the domains for which the zones should be created is reserved by IANA. 5. Security Considerations This draft does not introduce any additional security concerns. 6. Acknowledgements We would like to thank Michael Cretzman for his review of this document. 7. Authors' Addresses Levon Esibov Microsoft Corporation One Microsoft Way Redmond, WA 98052 EMail: levone@microsoft.com Stuart Kwan Microsoft Corporation One Microsoft Way Redmond, WA 98052 EMail: skwan@microsoft.com 8. References [RFC 2606] Eastlake & Panitz, "Reserved Top Level DNS Names" BCP32, RFC 2606, June 1999. [PRI] Coffey, S., Strain, S., Esibov, L., "DNS Top Level Domain For Private Networks in the Domain Name System (DNS UPDATE)", draft-coffeystrain-dnsext-privatednstld-00.txt, work in progress. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. Esibov & Kwan BCP [Page 3] INTERNET-DRAFT Suppressing DNS queries 22 February 2001 9. 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