[dns-operations] check if a domain has been registered via DNS

[Stephane Bortzmeyer]

On Fri, Apr 28, 2017 at 03:35:01PM +0800,
 Peng Yonghua <pyh at vodafonemail.de> wrote 
 a message of 125 lines which said:

> it's bad pratical that root zone has wildcards as it had got
> discussed here.

1) It's NOT the root zone. 2) Wether you like this policy or not, you
have to take it into account, or it seriously diminishes the value of
your tool.