installed ispconfig v18.104.22.168
it's using mydns and I figured out that to use old style 'blank' host names I had to use:
example.com. IN A 10.10.1.2
note the period at the end of the base domain name listed above.
ispconfig's interface (and I suspect mydns) was refusing
IN A 10.10.1.2
@ IN A 10.10.1.2
I even tried to escape "\" the "@" and the 'blank'
which didn't work either.
the 'blank' record was needed for 'NS', 'MX' records as well.
now it correctly resolves for:
dig @example.com example.com mx
before I could only get it to resolve for added machine names, like: