+
IETF DNSEXT WG Bill Manning
-draft-dnsext-opcode-discover-00.txt ISI
+draft-dnsext-opcode-discover-01.txt ISI
Paul Vixie
ISC
Erik Guttman
SUN
- 11 Apr 2002
+ 21 Dec 2002
The DISCOVER opcode
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119
-Abstract:
+0. Abstract:
The QUERY opcode in the DNS is designed for unicast. With the
development of multicast capabilities in the DNS, it is desireable
was developed as part of the TBDS project, funded under DARPA grant
F30602-99-1-0523.
-Introduction:
+1. Introduction:
This document describes an experimental extension to the DNS to receive
multiple responses which is the likely result when using DNS that has
full processing rules used by TBDS are documented here for possible
incorporation in a future revision of the DNS specification."
-Method:
+2. Method:
DISCOVER works like QUERY except:
address of the requester and the source address should reflect
the unicast address of the responder.
-Example usage for gethostby{name,addr}-style requestors:
+ Example usage for gethostby{name,addr}-style requestors:
Compute the zone name of the enclosing in-addr.arpa, ip6.int, or
ip6.arpa domain.
Cache all NS and A data learned in this process, respecting TTL's.
-TBDS usage for SRV requestors:
+ TBDS usage for SRV requestors:
Do the gethostbyaddr() and gethostbyname() on one's own link-local
address, using the above process.
zone names which match QNAME's, not with zone names which are owned
by QNAME's.
-The only deviation from the DNS[3][4] model is that a host (like, say, a
-printer offering LPD services) has a DNS server which answers authoritatively
-for something which hasn't been delegated to it. However, the only way that
-such DNS servers can be discovered is with a new opcode, DISCOVER, which
-is explicitly defined to discover undelegated zones for tightly scoped
-purposes. Therefore this isn't officially a violation of DNS's coherency
-principles.
+ The only deviation from the DNS[3][4] model is that a host (like, say, a
+ printer offering LPD services) has a DNS server which answers authoritatively
+ for something which hasn't been delegated to it. However, the only way that
+ such DNS servers can be discovered is with a new opcode, DISCOVER, which
+ is explicitly defined to discover undelegated zones for tightly scoped
+ purposes. Therefore this isn't officially a violation of DNS's coherency
+ principles. In some cases, a responder to DISCOVER, may not be traditional
+ DNS software, it could be special purpose software.
-
-IANA Considerations
+3. IANA Considerations
As a new opcode, the IANA will need to assign a numeric value
for the memnonic. The last OPCODE assigned was "5", for UPDATE.
- Test implementations have used OPCODE "6".
+ Test implementations have used OPCODE "6".
-Security Considerations
+4. Security Considerations
No new security considerations are known to be introduced with a new
opcode, however using multicast for service discovery has the potential
7. References
-[1] draft-ietf-dnsext-mdns-00.txt
-[2] draft-manning-dnsext-mdns-00.txt
-[3] RFC 1034
-[4] RFC 1035
- ----------------------------------------------------------
+Informational References:
+
+[1] Esibov, L., Aboba, B., Thaler, D., "Multicast DNS",
+ draft-ietf-dnsext-mdns-00.txt, November 2000. Expired
+
+[2] Woodcock, B., Manning, B., "Multicast Domain Name Service",
+ draft-manning-dnsext-mdns-00.txt, August 2000. Expired.
+
+Normative References:
+[3] Mockapetris, P., "DOMAIN NAMES - CONCEPTS AND FACILITIES",
+ RFC 1034, November 1987.
+[4] Mockapetris, P., "DOMAIN NAMES - IMPLEMENTATION AND SPECIFICATION",
+ RFC 1035, November 1987
+