© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Advanced IPv6 Topics Describing DNS in an IPv6 Environment

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Two DNS issues exist for IPv6: –IPv6 record support –IPv6 transport support IPv6 uses AAAA record for forward lookups PTR records for reverse Example of AAAA record: node5.example.com. INAAAA2001:db8:800:3abc:cc5::55b1 DNS-Supported Objects Node 5 node5.example.com 2001:db8:800:3abc:cc5::55b1 Node 4 node4.example.com 2001:db8:800:3abc:cc5::25e4

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Example of nibble format: $ORIGIN c.b.a b.d ip6.arpa. 4.e IN PTR node4.example.com. 1.b IN PTR node5.example.com. IPv6 reverse lookups use pointer (PTR) record, as in IPv4, but with new nibble format. Reverse Lookups DNS-Supported Objects (Cont.) PC2 Node 5 node5.example.com 2001:db8:800:3abc:cc5::55b1 PC1 Node 4 node4.example.com 2001:db8:800:3abc:cc5::25e4

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Primary DNS- Forward SOA=example.com 2001:db8:400:200c IPv6 uses updated version of DNS server and client resolver Structure is identical to IPv4 Root DNS servers not yet IPv6 transport-capable DNS Tree Structure Primary DNS- Forward SOA=example.com 2001:db8:400:200c Root DNS-ISC CA USA IPv4: IPv6: 2001:2001:db8:e:53 Routers PC1 node4.example.com 2001:db8:800:3abc:cc5::25e4 PC1 node4.example.com 2001:db8:800:3abc:cc5::55b1 Root DNS-WIDE Tokyo IPv6:2001:db8:f:3::35 Cache DNS B PC1 node45.example2. com Cache DNS B Primary DNS-Reverse SOA=2001:db8:800::/ :db8:700:abcd:: Primary DNS-Reverse SOA=2001:db8:800::/ :db8:600:ef12::

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Authoritative primary and secondary DNS servers support both IPv6 and IPv4 records: –Forward and reverse zones are not often on the same system. –Reverse zones are often maintained by ISP. Caching DNS is typically provided by ISP (home or small business) or by large enterprise for in-house clients. DNS Tree Structure Components DNS Tree Structure (Cont.) Secondary DNS-Reverse SOA=2001:db8:800::/ :db8:600:ef12:: Root DNS-ISC CA USA IPv4: IPv6: 2001:db8:e:53 Routers PC1 node4.example.com 2001:db8:800:3abc:cc5::25e4 Primary DNS-Forward SOA=example.com 2001:db8:400:200c PC2 node5.example.com 2001:db8:800:3abc:cc5::55b1 Root DNS-WIDE Tokyo IPv6:2001:db8:f:3::35 Cache DNS B PC1 node45.example2. com Cache DNS A Primary DNS-Reverse SOA=2001:db8:800::/ :db8:700:abcd:: Secondary DNS-Reverse SOA=2001:db8:800::/ :db8:600:ef12::

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Dynamic DNS Stage 4: Secondary DNS updated Stage 1: Keys configured on DNS server and client Stage 2: DHCPv6 used to configure IP addresses Stage 3: Primary DNS updated DDNS allows IPv6 clients to update resource records in the authoritative DNS server. Updates should be authenticated.

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Example Dynamic DNS Secondary DNS-Forward SOA=example.com 2001:db8:100::4e Primary DNS-Forward SOA=example.com 2001:db8:400::200c PC1 PC1 node45.example2. com (initial) 2001:db8:a::405 Primary DNS-Reverse SOA=2001:db8:800::/ :db8:700:abcd:: DHCPv6 Server

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Dynamic DNS (Cont.) Secondary DNS-Forward SOA=example.com 2001:db8:100::4e Primary DNS-Forward SOA=example.com 2001:db8:400::200c PC1 node45.example2. com (moved) 2001:db8:a::430 Primary DNS-Reverse SOA=2001:db8:800::/ :db8:700:abcd:: DHCPv6 Server

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Dynamic DNS (Cont.) Secondary DNS-Forward SOA=example.com 2001:db8:100::4e Primary DNS-Forward SOA=example.com 2001:db8:400::200c PC1 node45.example2. com (moved) 2001:db8:a::430 Primary DNS-Reverse SOA=2001:db8:800::/ :db8:700:abcd:: DHCPv6 Server

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Dynamic DNS (Cont.) Secondary DNS-Forward SOA=example.com 2001:db8:100::4e Primary DNS-Forward SOA=example.com 2001:db8:400::200c PC1 node45.example2. com (moved) 2001:db8:a::430 Primary DNS-Reverse SOA=2001:db8:800::/ :db8:700:abcd:: DHCPv6 Server

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v PC1 node45.example2. com (moved) 2001:db8:a::430 PC1 node45.example2. com (initial) 2001:db8:a::405 DHCPv6 client address may be updated in DNS by DHCPv6 server. It is more often used where DHCP and DNS are tightly integrated. No integrated DHCPv6 or DNS are on market today. DHCPv6 and DNS Implementation Dynamic DNS (Cont.) Secondary DNS-Forward SOA=example.com 2001:db8:100::4e Primary DNS-Forward SOA=example.com 2001:db8:400::200c Primary DNS-Reverse SOA=2001:db8:800::/ :db8:700:abcd:: DHCPv6 Server

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Summary IPv6 allows forward and reverse lookups, using AAAA records for forward lookups, and using PTR records in nibble format, rooted in ip6.arpa, for reverse lookups. IPv6 DNS tree structure is identical to IPv4 and contains root DNS servers, authoritative DNS servers, caching DNS servers, and client devices using the DNS resolver library. DDNS allows IPv6 clients to update resource records in the authoritative DNS.

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v