Working with ipv6/ipv4 and trying to understand how to debug issues...
And more specifically, I wanted to see if DNS was handing both ipv4 and ipv6 addresses.
So, on a mac, typing "host testsystem.example.com", it was returning both A (ipv4) and the AAAA (ipv6) addresses.
But on Debian, only the A address was returned.
Of course ""host -t AAAA testsystem.example.com" returned the AAAA record or the ipv6 address.
So, why did Debian not give me both A and AAAA.
The fix was to install bind9-hosts instead of hosts.
So, if you are running a debian workstation, you might find it helpful to run "sudo apt-get install bind9-host" which will make it replace the hosts package.