1. 1IETF59 DNSOP WG IPv6 DNS Discovery Issues Jaehoon Paul Jeong ETRI paul@etri.re.kr http://www.adhoc.6ants.net/~paul/ 1st March 2004 59th IETF – Seoul, Korea

2. 2IETF59 DNSOP WG Recent Decision on IPv6 DNS Discovery DNSOP Decision –ADs and Chairs have decided to produce a document outlining the attributes of three DNS discovery approaches; RA Option DHCP Option Well Known Addresses Document of IPv6 DNS Discovery –Describes the outstanding problems and issues with IPv6 DNS Discovery –Details the following things; Operational attributes of each solution Various deployment scenarios Analysis of a multi-solution resolution Etc.

3. 3IETF59 DNSOP WG DNS Discovery Approaches RA Option (draft-jeong-dnsop-ipv6-dns-discovery-01.txt) –RA DNS Server option –It can be delivered to IPv6 Host along with IPv6 Prefix Information option. DHCP Option ( draft-ietf-dhc-dhcpv6-stateless-04.txt, RFC 3646) –DHCP Recursive Name Server option –It can be delivered to IPv6 Host by either DHCPv6 server or Stateless DHCPv6 server (DHCP-lite). Well Known Addresses (draft-ohta-preconfigured-dns-01.txt) –Preconfigured Well Known Anycast Addresses –It can be preconfigured in IPv6 Host.

4. 4IETF59 DNSOP WG How to apply each approach? - 1/2 Ordering between RA Option and DHCP Option –Criterion? M and O flags O flag M flag 01 0 - Address: RA - DNS Server: RA -Address: RA -DNS Server: DHCP 1 -Address: DHCP -DNS Server: RA -Address: DHCP -DNS Server: DHCP

5. 5IETF59 DNSOP WG How to apply each approach? - 2/2 Ordering between two Options and Well-known Addresses –Criterion? Well-known Addresses are last resort. –When IPv6 Host cannot get DNS server information though both RA and DHCP. IPv6 Host can configure Well-known Addresses as the most preferable in its configuration file. IPv6 Host can get the explicit fact that Well-known Addresses for DNS can be used in the site through RA Hint Option. –RA Hint Option indicates that Well-known addresses can be used for DNS name resolution. –RA Hint Option can be implemented by RA DNS Server Option with a new flag, Well-known Addresses for DNS.

6. 6IETF59 DNSOP WG Deployment Scenarios Prefix Delegation Environment –When a leaf router gets a subnet prefix though Prefix Delegation protocol, such as DHCP, DNS server address(es) can be piggybacked. –Leaf router advertises DNS server address(es) with RA options. Mobile Environment –MIPv6, HMIPv6 and NEMO Through RA Options, DNS Server Addresses can be piggybacked with CoA Prefix Information. –There is no additional delay to discovery DNS Server. Well-known addresses can be used for DNS name resolution. –If Hint option for Well-known addresses is used together, Mobile Node will be convinced that it can be served.

7. 7IETF59 DNSOP WG Discussion Any questions or comments…