Thanks Chris, thought you were still busy with moving else I would have
singled you out to start with.  Anyway, a couple of points many may be
interested in as relates to mail-bounce-sensitive listservs...

Chris Bartram wrote:  [...big snip...]

>  Now it finds itself as the next [MX] in the list; this causes it
>  to give up and queue the mail for another try later.

That is what I was after.  This eliminates the "simple" loop of sending
to yourself.  Then we have the case of hosts a/b/c acting as mutual
backup, and I have seen cases of b/c looping mail destined for a.  Then
there is the mysterious sendmail error "Configuration error - host not
recognized as local" or " - MX record points to myself", the latter
being an MX only site.  But anyway, my immediate question answered, just
looking for more detail on how I handle mail bounces from the list.

> > If the latter how is this conveyed to sendmail
> > (Solaris), LSMTP (NT), and/or NetMail (MPE/iX)?
> [NetMail follows the same rules as all other SMTP MTAs (are supposed to)].

I think my "loop" involved your "hide-hostname" feature (and my
mis-configuration thereof).  <plug> NetMail and relatives have their own
DNS resolver which understands MX records (and other things) that MPE's
resolver doesn't; a relatively recent addition which made it a truly
robust MTA </plug>.

> If you want to prevent the undeliverable/undeliverable-yet messages,
> then just the MX entries for hosta would do; assuming hostb doesn't
> send out those undeliverable-yet messages. To end-users systems, mail
> would have been accepted by a defined proxy and their mailers would
> treat the mail as having been delivered (to another MTA at least, if
> not delivered to final destination).

> Lots of sites use this same scheme to handle e-mail delivery when they
> only have part-time (dial-up) Internet connections; If they're on-line
> when the mail is sent, they get it directly. If not, then it goes to
> the next choice on the MX list; usually a system(s) at their ISP. While
> they're not online, mail gets queued up on their ISP's system, and next
> time they connect the ISPs system (during one of its retries) reaches
> their system and delivers all the mail for them in its queue.

If you fit into the above category (you have an actual MTA on a dialup,
doesn't apply to POP services) then HEAR ME OUT!  The vast majority of
junk mail bounces I receive on the list are of the "Warning:
Undeliverable for xx hours" variety, most default to 4 hours for the
first notice and daily thereafter.  This is fine for connections that
are expected to be permanent, but outright annoying if you only dialin
once or twice a day.  It's not your fault, it's your ISP.  If you
support dialup MTAs you should be more tolerant with these bounces.  I
won't name names :-) but there are some perpetual pests out there :-)

Jeff Kell <[log in to unmask]>