[dns-operations] Why would an MTA issue an ANY query instead of an MX query?

[Zuleger, Holger, Vodafone Germany]

> > What about rate limiting clients which are not keeping the 
> TTL value?
> > We are talking about rate limiting on authoritative name 
> servers, right?
> 
> Not *only* on authoritative name servers. It is also relevant for
> recursive name servers.
In general, yes of course. But I had ANY querys and the current
amplification attack in mind.