Has anyone seen a Windows Server return zero results to a CLDAP query for NetLogon servers?

[Jeremy Allison]

On Fri, Oct 04, 2019 at 06:40:22AM -0700, Richard Sharpe via samba-technical wrote:
> >
> > After that Samba seems to declare that DC as a negative connection
> > entry and cannot find any DCs.
> >
> > Has anyone seen this? Does anyone know how to configure Windows to do that?
> 
> Hmmm, according to the following a DC returns such a result if the
> filter is invalid:
> 
> https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-adts/249949c1-484c-48ad-b548-a31dd0ab2c93

So the relevent question for Samba is - should we consider that
a negative connection entry and add it to the cache ? Or just
drop the reply and not add anything to the cache in the hope
we can get a better response ?