Re: qmail-tcpto and non-authoritative DNS

[D. J. Bernstein]

Fred Lindberg writes:
> Would it make sense to have a similar table (or put into the same
> table) also host for which authoritative DNS is not available?

DNS caching is the responsibility of your local name server. Old servers
supported only ``positive caching''; new servers also support ``negative
caching,'' which includes caching temporary failures.

---Dan