Setup IPv6 reverse delegation
How to determine which reverse zones/ip6.arpa domains are relevant to a given IPv6 address block
The mapping of IPv6 reverse DNS zones must be made on nibble boundaries. That means, that if your official IPv6 address block does not have a prefix length divisible by 4, you have to split it in multiple reverse zones. GestióIP's free online subnet calculator offers a tool to determine easily this address blocks and to map them to the corresponding ip6.arpa domains.
Example of a reverse delegation for domains on nibble boundaries:
You have been allocated the address block 2001:db8::/32. As a prefix length of 32 is divisible by 4, you can map your address block directly to the corresponding ipv6.arpa domain.
Calculate the IPv6 address range: Introduce your allocated address block, select a prefix length and press "calculate".
The subnet calculator shows the ipv6.arpa format of the introduced IPv6 address. The prefix part appears in black characters.
Use only the prefix part for the reverse delegation. The reverse zone for the address block 2001:db8::/32 is 8.b.d.0.1.0.0.2.ip6.arpa.
Example of a reverse delegation for domains on non-nibble boundaries:
You have been allocated the address block 2001:db8::/29. As the prefix length 29 is on a non-nibble boundary, you have to find the next bigger prefix length that is divisible by 4.
Calculate the IPv6 address range: Introduce your allocated address block, select a prefix length and press "calculate".
The prefix length which appears in green represents the next bigger prefix length which is on a nibble boundary. Click over the green prefix length.
The subnet calculator shows the first and the last address block which is on a nibble boundary. Click over this range.
The output is the complete list of the corresponding ip6.arpa domains/reverse zones.
GestióIP Copyright © Marc Uebel 2012