domain name system - Best practices for IPv4/IPv6 hosts in DNS zones?

I've got a VPS with IPv4 and IPv6 addresses, and I'd like to use them both for my website and other services I might use. I've added a "www" register both with "A" and "AAAA", and I've done the same for the "ns" register. Is this "the Right Way", or should I use different names for the IPv6 part? (i.e., "www6", "ns6", etc.)

Thanks in advance.

Answer

IMHO, it depends on what you want.

If you're using both protocols (v4 and v6) to offer the same service (eg IMAP/S, or HTTP, or whatever), and you want clients to be protocol-transparent - that is to say, if you want v6-enabled clients to use v6, and others to use v4, and no-one to care about which they're using - then use the same hostname in each record.

If you want people to be able to select protocol by hostname, use different hostnames for A and AAAA records.

So, for my webserver, where I want clients to be protocol-agnostic, I use the same hostname:

www.teaparty.net.   3600    IN  A   178.18.123.145
www.teaparty.net.   3600    IN  AAAA    2a01:8000:0:4::1:1

For my ntp pool server, where I decided I'd like people to be able to select the protocol, I used different ones:

ntp.teaparty.net.   3600    IN  A   178.18.123.148

ntp6.teaparty.net.  3600    IN  AAAA    2a01:8000:0:4::123:123

Work out what client behaviour you wish to encourage, and make policy accordingly.