* Marc Sherman:
>> Does this problem sound familiar?
>
> Very familiar. It happened to me in June[0], and we were just
> discussing it again earlier this week[1].
Ah, the good old morphogenetic field.
> Anyway, while Philip will probably have some questions for you to help
> track down and debug the problem, there is an easy workaround in your
> host has no real IPv6 connectivity:
>
> http://www.exim.org/mail-archives/exim-users/Week-of-Mon-20051128/msg00043.html
I'm the one who has working IPv6 connectivity, it's other hosts I'm
worried about. 8-/
Note that the failing domains I've seen so far have an MX record
pointing to an A/AAAA combination, and it seems that Exim somehow
applies the AAAA retry hint to the A host, possibly if the A host is
temporarily unreachable as well.