6to4 Reverse DNS Delegation

A visitor to my blog informed me that the Number Resource Organization (NRO) is the authority for 6to4 reverse DNS delegation. The delegation is done at https://6to4.nro.net/. I am really surprised as I have always wanted to set reverse lookup of my 6to4 address in order to set up SMTP service.

Since I am using the IP address 202.81.252.116, upon converting to 6to4 address, I own the IPv6 address prefix of 2002:ca51:fc74::/48. The requirements to meet 6to4 RDNS delegation are very strict:

1. The requester must use a 6to4 IPv6 address to visit the web site.

2. Only RDNS delegation of a /48 prefix related to the visiting IPv6 address is allowed.

3. The website knows which /48 prefix is to be delegated by checking on the visiting 6to4 address. There is no need for the requester to make any input.

4. The nameservers must have the proper configuration in place to handle the reverse lookup of the /48 prefix before requesting the delegation. Once the submit button is clicked, reverse lookup will be checked and if there is anything wrong, the delegation will not be successful.

I fully support these rules as they are designed to verify who own a 6to4 address range.

Hopefully, I passed all the check. I am now able to do “dig –x 2002:ca51:fc74::1” which points to “ipv6.warrenkwok.com”.

I like to give a big thank to the Number Resource Organisation.