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unixtippse
Asked: 2010-11-06 23:40:30 +0800 CST

IPv6 AAAA vs. CNAME for same domain name

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I reach my home site through a DynDNS name, and also have tunneled IPv6 there.

In the DNS zone, I have:

myhomesite CNAME example.dyndns.org.

How do I simultaneously point "myhomesite" to an AAAA record? If I trivially make it

myhomesite CNAME example.dyndns.org.
myhomesite AAAA  2001:db8::1:2:3:4

the zone is invalid (CNAME and other data).

Can you suggest a way for having the CNAME record and the AAAA record visible behind the same domain name?

What I'm not looking for is an ".ipv6."-infixed record, which already is in place.

domain-name-system cname-record

1 Answers

  1. Best Answer

    I copy from DNS for Rocket Scientists:

    CNAME RRs cannot have any other RRs with the same name, for example, a TXT - well that was true until DNSSEC came along and in this case RRSIG, NSEC and certain KEY RRs can now occupy the same name.

    Therefore what you want to do cannot be done using a CNAME. Use the CNAME to access your homesite via IPv4 and have a myhomesite-v6 AAAA record point to the IPv6 address

    If you do not want such a solution, you have to implement a mechanism that updates your DNS zone each time your IP address changes with:

    myhomesite IN A IPv4.add.ress
           IN AAAA IPv6.add.ress

    But that depends on the API (if any) that your DNS provider exports to you. For example if I had root access on the DNS server, I would periodically host -t a example.dyndns.org and use the output to update the zonefile with the IPv4 address for myhomesite.

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