Below is a draft of the document Gerhard, Linus and Marcos have been working on. It's been circulated to the list for discussion. Marcos will be giving a presentation on this at the WG meeting next week. Please submit any comments to the authors or, better still, to the mailing list. draft-whois-srv-01.txt Linus Corin Marcos Sanz Gerhard Winkler 24 April 2002 Using DNS SRV records to locate whois servers Status of this Memo This document is a draft on the usage of the DNS SRV RR for the location of whois servers. Abstract There is no common whois database where all domain objects are stored. Several TLDs run their own databases, which can be reached under different network locations and, for the user, there is no easy way to find the right whois server to answer their query by means of a simple whois client. This situation can be improved by using DNS SRV records and SRV-cognizant whois clients. 0. Definitions The key words "MUST", "SHOULD", and "RECOMMENDED" in this document are to be interpreted as described in [RFC 2119]. Other terms used in this document are defined in the DNS specification, [RFC 1034]. 1. Format The general format of DNS SRV records is documented in RFC 2782: _Service._Proto.Name TTL Class SRV Priority Weight Port Target Therefore the simplest format of an SRV record to locate a whois server is: _whois._tcp IN SRV 0 0 43 whois.nic.example. [RFC 1700] foresees the possibility of a whois service over UDP. Common use is TCP but nothing would prevent from analogously setting the _Proto field to the value _udp. The symbolic name of the service is defined as "whois" (case insensitive), which is the most familiar name, though it is also called "nicname" in [RFC 954]. Priority and Weight have a value of 0 in the example above just for readability purposes. It is RECOMMENDED to use the port number 43, as specified in [RFC 1700] or [IANA-NUM]. 2. Usage If there is a whois server running for a specific domain, such an SRV record can be defined. When used for looking up information about a domain, whois clients can do DNS lookups for SRV records, and can use the retrieved target information to point their whois queries accordingly. This kind of client is called "SRV-cognizant" or "SRV-aware" whois client. It is imaginable that this functionality could be extended for other purposes (like inetnum or handle lookup), but this remains open for a future discussion. 3. Restrictions The service record functionality is meant as an extension to the existing whois service and not as a new service. In the absence of a whois protocol whose specification calls for the use of other weighting information, the field Weight in the SRV record keeps the standard meaning specified in [RFC 2782]. As defined in [RFC 2782] the client SHOULD abort if it finds a record defined like: _whois._tcp IN SRV 0 0 0 . The given SRV record is valid for the zone where it appears. This means that it does not provide any information on subdomains or zones below; it is a onelevel information. Search for subdomains MUST behave like conventional DNS search algorithms. 4. Authority There is no authority which defines who should run a whois server, though it is usual that the TLD registry runs a whois service for the zone where it is authoritative. There is no definition of which target should be used as a default for an SRV-cognizant whois client if no whois server could be discovered by means of SRV records. The use of a default whois server is local dependent. 5. Security Considerations The same security considerations as defined in [RFC 2782] should apply. There is no discussion on security, data protection and privacy relating to the contents of the whois server in this paper. This is the responsibility of the whois server operator and has nothing to do with a mechanism that describes how whois servers can be reached. 6. References [RFC 954] NICNAME/WHOIS [RFC 1034] Domain names - concepts and facilities [RFC 1700] Assigned Numbers [RFC 2119] Key words for use in RFCs to Indicate Requirement Levels [RFC 2782] A DNS RR for specifying the location of services (DNS SRV) [IANA-NUM] www.iana.org: Directory of General Assigned Numbers 7. Authors' Addresses Linus Corin Telia International Carrier 4th Floor, 330 High Holborn WC1V 7QY London, United Kingdom linus@telia.net Marcos Sanz DENIC eG Wiesenhuettenplatz 26 D-60329 Frankfurt/Main, Germany sanz@denic.de Gerhard Winkler Vienna University Computer Center / NIC.AT Universitaetsstrasse 7 A-1100 Vienna, Austria gerhard.winkler@univie.ac.at