Application Note
Last Updated: April 2006
INTRODUCTION
RFC 1886-DNS Extensions to support IP version 6, published in December 1995, defined the IP6.INT domain to provide a way of mapping an IPv6 address to a host name.
RFC 3152-Delegation of IP6.ARPA, based on IAB recommendations that the ARPA top level domain be used for technical infrastructure sub-domains when possible, was released in August 2001. It resulted in the creation of the IP6.ARPA domain for address to DNS name mapping for the IPv6 address space, deprecating the usage of IP6.INT as documented in RFC 4159, Deprecation of "ip6.int," August 2005.
As a result, all Regional Internet Registries (RIRs) will stop the maintenance of the IP6.INT domain on June 1st 2006.
Reminder: The experimental 6bone infrastructure will be phased out on June 6th 2006 as documented in RFC 3701; the 6bone (IPv6 Testing Address Allocation) phase out took place in March 2004.
EVALUATING THE IMPACT ON CISCO IOS IPV6 DEVICES
Initial releases of Cisco IPv6 products do support IP6.INT for the DNS Resolver feature. Following the publication of RFC 3152, the implementation has been updated to also support IP6.ARPA.
The minimum software releases to run for IP6.ARPA support are:
• Cisco IOS Software 12.3(12)
• Release 12.3(11)T
• Release 12.4(1)
• Release 12.4(2)T
• Release 12.2(28)SB
• Release 12.2(18)SXE on the Cisco Catalyst 6500 Series Switch and Cisco 7600 Series Router
• Release 12.2(25)EWA on the Cisco Catalyst 4500 Series Switch
• Cisco Catalyst 3560 and 3750 Series Switches-Release 12.2(25)SED
• Release 12.0(32)S2 for Cisco 10720 and 12000 Series Routers
• Cisco IOS-XR Software Release 3.0
CONCLUSION
The update of Cisco IPv6 products to one of the above release before June 2006, when IPv6 and DNS Resolution for IPv6 are configured on a given device, is strongly recommended.
REFERENCES
RFC 1886: http://www.ietf.org/rfc/rfc1886.txt
RFC 3152: http://www.ietf.org/rfc/rfc3152.txt
RFC 3701: http://www.ietf.org/rfc/rfc3701.txt
RFC 4159: http://www.ietf.org/rfc/rfc4159.txt
