>     Roger> One difference is that qmail apparently always sends a separate
>     Roger> copy of a message to each recipient and may open up many
>     Roger> connections in parallel to do this.
>
> yes it does this.
>
>     Roger> for faster delivery in common cases, it might bite you if you
>     Roger> have a mailing list (as we do) with hundreds or thousands of
>     Roger> subscribers on a small number of hosts.
>
> bite whom?  the sending site or the receiving site?

It's the receiving host I am worried about in this case.  If 5000 separate
messages arrived in a short period of time, I know of at least one of our
hosts that would have trouble dealing with it.  Probably some of the others
would too.  50 copies of a message with 100 recipients each are much easier
for it to handle.

>     Roger> Also, I don't think that qmail generates bounces in the Internet
>     Roger> DSN format that can be automatically interpreted by LISTSERV.
>
> this is a non-issue.  the largest source of bounces for any well know list
> is aol.  e.g.

That's not true for my lists.  I have AOL subscribers, but they do not
generate the majority of bounces on my lists.  I suppose it's related
to the subjects that the lists cover.  Anyway, AOL has stated that they
are working on implementing bounce messages in DSN format.

> qmail does two things listserv admins like -- 1) it has wildcard address so
> probing works and 2) it's trivial* to fix gross things like the aol bounce
> above.

Probing is good.  There's a probe interface for sendmail, but it's
not supported by L-Soft.

> the same script that rewrites the aol bounce to dsn also converts qmail's
> qsbmf format.
>
> *well some formats like aol's are easy to do.  some are a lot harder so we
> don't bother.

I'm not really interested in being in the business of producing scripts to
rewrite bounce messages.