A records point to a domain
stanislav shalunov
shalunov at att.com
Fri May 19 21:23:19 UTC 2000
Barry Margolin <barmar at genuity.net> writes:
> If step 3 fails because the nameservers don't respond, the MTA
> should give up immediately and put the message back in the queue to
> be retried later, precisely to prevent the above bug. Why would
> they even consider going on to step 4?
Of course. I have checked sendmail 8.9 source, and naturally it does
it this way. However, I could imagine an MTA author who creates a
function that returns a list of MX records or a failure + sets an
error-type global (a la errno). They could just go on to see if an A
record is available if that function returns *a* failure.
Obviously, this behavior isn't desirable, but it would be hard to
detect it with testing. So I assumed that there might be MTAs out
there that do it, since it seems a very natural mistake to do, and can
live in the code for a long time unnoticed.
As you point out later, the standards don't explicitly prohibit such
behavior (unfortunately).
--
stanislav shalunov | Speaking only for myself.
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