Re: Penelope builds a kernel

[James Antill <james@and.org>]

"Eric S. Raymond" <esr@thyrsus.com> writes:

> Benjamin LaHaise <bcrl@redhat.com>:
> > FYI, it's easy to fix, just use the correct ordering of download, transmit, 
> > delete that sendmail and other MTAs use.
> 
> I don't understand what you think you're seeing, but I am sure of
> this; if I had been enough of a drug-addled lunatic to allow fetchmail
> to delete mail before getting a positive acknowledge from the
> downstream MTA, someone in the pool of over two thousand people who have sent
> me bug reports and patches would have called me on it some time in the
> six years of production use well before *you* entered the picture.
> 
> It's likely you're being hosed by an MTA that's sending back bogus 2xx
> responses.  That's happend before.  Fetchmail can't magically cope
> with MTAs that tell it lies.
> 
> Fetchmail *already works the way you recommend* -- as any idiot can
> verify by reading the short section of the main driver loop where
> dispatch and delete takes place.  That's been an invariant of the code
> since day one, and you thus clearly have no bloody idea what you are
> flaming about.

 I'll bite, as I've been forced to use it at times.

1. User configures fetchmail to download from imap/pop3 account (with
the messages kept on the server and just recorded -- Ie. nothing is
deleted server side).

2. User has exim as local transport, and also gets normal SMTP
traffic.

3. User enables sender_verify, sender_verify_hosts_callback and
sender_verify_callback_domains which catches loads of spam and is
happy.

 Then...

. User runs fetchmail
. fetchmail feeds email to exim
. exim does callback verification, and refuses email.
. fetchmail pretends it has delivered email, so _even if_ you hack your
  MTA to say don't verify from localhost lost emails will never be
  delivered by fetchmail (even though they are still on the server,
  and fetchmail knew they didn't get sent).

...and that assumes that you swallow the argument that you should have
to reconfigure your MTA to work around fetchmail bugs.

-- 
James Antill -- james@and.org
The Hurd itself is aggressively multi-threaded and all of the locking has
been done with an eye towards multi-processor systems. That said, we have
not yet used a microkernel that stably supports multiple cpus.