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IPv6 DNS Discovery, and why it is important. Bob Hinden. IPv6 AUTOCONFIGURATION. IPv6 Neighbor Discovery and Stateless Auto-Configuration Defined in RFC2461 and RFC2462 Provide the ability to Learn Prefixes, Link Information (MTU, etc.), Routers, Resolve addresses, etc.
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IPv6 DNS Discovery,and why it is important Bob Hinden
IPv6 AUTOCONFIGURATION • IPv6 Neighbor Discovery and Stateless Auto-Configuration • Defined in RFC2461 and RFC2462 • Provide the ability to • Learn Prefixes, Link Information (MTU, etc.), Routers, Resolve addresses, etc. • Create Unicast Addresses • Everything to become a functional IPv6 node, except: • Resolve Names
IS THIS A PROBLEM? • An IPv6 node that can’t resolve names isn’t very useful • Can’t use URLs, host names, etc. • IPv6 Addresses are difficult to type by people • 1080:0:0:0:8:800:200C:417A • Name resolution is a basic IP service • They even provide a basic form of service discovery • ftp.ietf.org, www.ietf.org, ntp.ietf.org, ….
MISSING FEATURE • The lack of the ability to resolve names is a missing feature of IPv6 Stateless Autoconfiguration • Hasn’t been a big problem in the past, because • Most AAAA records have been retrieved via IPv4 • Native IPv6 DNS is now being deployed • Solution is needed soon • Lack will slow down IPv6 deployment • Discourage non-standard solutions
WHAT IS NEEDED • Main requirement • Learn the address of one or more IPv6 Recursive DNS servers • Lifetimes (?) • Nice but not required • Default domain (DNS suffix) • Default search list • Other? • Non-Requirements • General service discovery solution
SOLUTION SPACES • Create Neighbor Discovery Router Advertisement Option • Simple, gives router administrator control • Router likely has information anyway • Finishes IPv6 Autoconfiguration • Create well known addresses for IPv6 DNS Resolvers • Like old <draft-ietf-ipv6-dns-discovery-07.txt> approach • Could use new Local Addresses or Global Addresses
WHY NOT DHCPv6 • Overkill if only DNS Recursive Server information needed and DHCP isn’t being used for address assignment • Stateless DNS? • IPv6 Autoconfiguration works better than DHCPv4 in dynamic environments • IETF meetings are a good example • Practical problems • DHCP RFC isn’t out yet • Little experience
SUMMARY • The ability to resolve names is missing from IPv6 Autoconfiguration • IPv6 Nodes are not very useful if they can’t resolve names • Standard solution needed soon