UNIX hosts and MX "best practice"

[Barry Margolin]

In article <38923A98.4F126B1B at daimlerchrysler.com>,
Kevin Darcy  <kcd at daimlerchrysler.com> wrote:
>Newer sendmails use ANY queries to avoid this performance problem.

I've heard this said many times, but I don't understand how it can work
reliably.  How do they deal with the fact that a caching server responds to
ANY queries only with the data it happens to have cached, so the response
might not be complete?

The only way that I can imagine this working is if sendmail implements its
own iterative resolver, rather than using a caching server, so it's always
querying the authoritative servers.  But that wouldn't work for sendmails
behind a firewall.

-- 
Barry Margolin, barmar at bbnplanet.com
GTE Internetworking, Powered by BBN, Burlington, MA
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