Bare TLD resolutions

[johnl at iecc.com (John Levine)]

>The latter would seem to be avoidable by making sure that *DNS resolution
>of bare TLDs always returns NXDOMAIN*.
>
>Is that a requirement for a TLD?

No. In fact, a TLD lookup that returned NXDOMAIN would be utterly
broken since that would mean the TLD had no SOA, no NS, and no
subdomains.  Perhaps you're confusing it with NOERROR.

>If it isn't, does anyone know of any domains dumb enough to actual 
>return something for a lookup on the bare TLD?

Yes.  If you'd read RFC 7085, you'd already know which ones do.

There have been A and MX records at TLDs nearly as long as there have
been TLDs.

R's,
John