DNS Discovery is absent from IPv6 Auto-Configuration. ... 2

1
IPv6 Router Advertisement basedDNS
Autoconfiguration
draft-jeong-ipv6-ra-dns-autoconf-00.txt

• Jaehoon Paul Jeong
• ETRI paul_at_etri.re.kr http//www.adhoc.6ants.net/
  paul/
• 14th July 2003
• 57th IETF Vienna, Austria

2
Motivation of the Draft

• DNS Discovery is absent from IPv6
  Auto-Configuration.
• DNS Discovery through Neighbor Discovery is
  needed.
• If both IPv6 Address and DNS Information can be
  autoconfigured simultaneously, the additional
  delay for finding out DNS Information can be
  saved.
• Using DHCPv6 requires some delay for
• Discovery of DHCPv6 Server
• Message exchanges between the IPv6 Host and
  DHCPv6 Server.
• Especially, the time for DNS discovery in
  Wireless Networks is important,
• Such as MIPv6, HMIPv6, NEMO and MANET.
• We need a simple DNS Autoconfiguration mech.
• DNS Discovery for DNS Name Resolution
• Auto-Registration of Host DNS Name

3
Idea of the Draft

• 1. RA-based DNS Discovery
• Autoconfiguration of Recursive DNS Server (RDNSS)
• RA message announces DNS Information to IPv6
  hosts.
• An IPv6 host can configure the address of
  RDNSS(es) placed in the local or visited network.
  
• Optimization of DNS Name Resolution
• is possible by using the local RDNSS placed in
  the same network.
• 2. Auto-Registration of Host DNS Name
• A User-preferred Host DNS Name, including the DNS
  zone suffix of the local or visited network, can
  be registered with DNS server through DNS Dynamic
  Update.

4
DNS Option format
0 1 2
3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6
7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 ---------
-----------------------
Type Length Pref A
Reserved ----------------
----------------
Reserved
-----------------------
---------



IPv6
Address of DNS Server




------------------------
--------

DNS Zone Suffix

---------------
-----------------
5
Procedure of DNS Autoconfiguration
IPv6 Host
Router
DNS Server
(RS)
RA w/ DNS option
DAD NS

• 1. DNS Discovery 2. DNS Name
  Auto-Registration

no NA
DNS Request for checking DNS Name duplication
DNS Response
DNS Request for registering AAAA resource record
DNS Response
6
RA-based DNS Discovery

• 1. Discovery of Recursive DNS Server (RDNSS)
• For DNS Name Resolution
• IPv6 Host can select the nearest RDNSS
• On the basis of Pref field in DNS Option and
  the longest prefix matching between the RDNSSs
  and Hosts IPv6 addresses.
• 2. Discovery of DNS Zone Suffix
• For DNS Name Auto-Registration

7
Application of DNS Autoconfiguration
Optimization of DNS Name Resolution in
HMIPv6ltdraft-jeong-hmipv6-dns-optimization-01.txt
gt
8
Host DNS Name Auto-Registration

• 1. Generation of DNS Name
• Combination of User-preferred ID and DNS Zone
  Suffix
• User-preferred ID
• E.g. Paul, Paul-1, Paul-2, etc.
• DNS Zone Suffix
• is provided by DNS Option in RA message.
• 2. Verification of the Uniqueness of DNS Name
• Duplicate Name Detection through DNS Dynamic
  Update
• 3. Host-initiated Registration of DNS Name
• IPv6 Host can register its DNS name and IPv6
  address through DNS Dynamic Update by itself.

9
Considerations for DNS Dynamic Update

• Allowance of Auto-Registration from an
  unidentified IPv6 host
• Through AR-bit (Auto-Registration) in Header
  Section
• We can limit the kinds of dynamic update
  operations
• Allowance of adding a new AAAA resource record
• Allowance of modifying its own AAAA resource
  record
• Denial of deleting other hosts AAAA resource
  records

10
Header Section format inDNS Dynamic Update
0 1 0 1 2 3 4 5
6 7 8 9 0 1 2 3 4 5 -------------
-------------------
ID -------------
------------------- QR Opcode AR
Reserved RCODE -------------
-------------------
ZOCOUNT -------------
-------------------
PRCOUNT -------------
-------------------
UPCOUNT -------------
-------------------
ADCOUNT -------------
-------------------
AR-bit Auto-Registration
11
Discussion

• This draft can be divided into two separate
  drafts.
• RA-based DNS Discovery
• Extension to DNS Dynamic Update for Host DNS Name
  Auto-Registration
• How about dnsop wg draft?
• In order to discuss DNS Autoconfiguration
  including DNS Discovery.
• Any questions or comments