Eric,
After observing the configuration questions from users here and in
de.comm.software.mailserver, the most common problem with the multidrop
user interface seems to be that users don't configure the "envelope"
option properly.
I therefore suggest that fetchmail 6.3 and newer do the following:
* refuse multidrop configuration unless "envelope" is _explicitly_
configured (and tell the user he needs to configure the envelope
option) and change the envelope default to nil.
* unless fetchmail already does that, treat a delivery as "temporarily
failed" (leaving the message on the server, not putting it into
.fetchids) when the header listed in the "envelope" option is not
found.
And, unless the "mda" option is fixed by the time, also:
* refuse the mda option for multidrop configurations unless it contains
the substring "sendmail"
* refuse the mda option always if it contains the substrings "sendmail"
and "-t".
The last two are meant to avoid mail loops by some ignorant trying to
inject into sendmail in "parse-headers-for-addresses" mode (-t), which
must not happen.
I'd also like to discourage injecting into custom programs such as
qmail-inject, because qmail _has_ a "good enough" /usr/sbin/sendmail.
--
Matthias Andree