[atlas] Probe DNS entry A more useful than AAAA for dynamic IP hosts

	Hello everybody,

I have just received and put in service my probe. This is my first post to the list (I have been monitoring the traffic for a while: none).
I wish to take the chance to admire the design and compact packaging ! Great work!

Back on topic, for us low-lies with dynamic IP addresses using the probe DNS entry (maybe with a CNAME entry) could be a great way to ensure our Dynamic DNS entries are up to date and our network could be reached from remote.

I am running a full IPv6 network receiving a /48 from Hurricane Electric and the probe tend to select (at least in my short experience) the autoconfigure (from MAC) IPv6 address as its Internet Address to use in the DNS record:

fabio at atlantic:~$ host -t A pdxxxxx.probes.atlas.ripe.net
pd456a699.probes.atlas.ripe.net has no A record
fabio at atlantic:~$ host -t AAAA pdxxxxx.probes.atlas.ripe.net
pd456a699.probes.atlas.ripe.net has IPv6 address 2001:470:xxxx:2:220:4aff:fee0:xxxx
fabio at atlantic:~$

I saw that there are plans (in the FAQ) to add support both for AAAA and A records at the same time but I believe it would be beneficial for users to be able to select which record is generated or have the A record as default while waiting for the support for both to be implemented.

Thanks for listening.

Fabio