[ILUG] Strange Fetchmail/sendmail/"delivery failure notification" mail b ehaviour . . . .

[John_White at dell.com]

A strange thing I noticed about Fetchmail, sendmail, returned (due to
failure) mails and the lotto numbers. . . .

<preamble>
	Over the last few weeks I was having problems with fetchmail and
gofree(.indigo.ie). I have 3 people at home who read mail from gofree, so I
set up the email caching server with Donncha's install-sendmail scripts
(thanks very much Donnacha). Everything was working  great until my own
account on gofree started acting strangely. Whenever I ran fetchmail, it
reporting a "SMTP error 553 (user address required <@pop.indigo.ie>)" and
then rambled on about a socket error. This wouldn't have been so bad except
it then failed to process other mails on the pop server. I wasn't in an
immediate hurry to fix it until someone else's mail went the same direction
and I had to think about it.

	While fixing it this weekend, (I ended up having to configure
Outlook Express to read directly from the mail server, and I retrieved mail
for each user separately) I found out the (probable) cause. In the case of
each user, the first mail retrieved (then one causing the error) was a
return mail due to message delivery failure (on behalf of indigo's server).
It seems that Outlook (which only fetches the mail) had no problem
retrieving the offending mails, but fetchmail (which retrieves the mail and
forwards to port 25 or wherever you configure it to) did have a problem. The
probable problem is that my local sendmail, listening on port 25 took
exception to these mails, and fetchmail (as is designed to do) broke out.
</preamble>

	It seems a little strange that fetchmail barfs (or more accurately
my sendmail barfs) when it gets back a "delivery failure" notification mail
for a local user. I was wondering if anybody knows of a fix for this, it
doesn't seem to be mentioned anywhere in any documentation/FAQ/discussion
group. I'm sure fetchmail ( & sendmail ) are supposed to handle these things
correctly so It's probably a case of "we need more info". In the meantime
I'm asking people at home to be **careful** when typing email addresses (ok
it'll help), but it's a bit unacceptable really . . . . Anyway, any thoughts
or insights would be much appreciated, a solution would be great.

Oh, while I'm at it, is there a "nice" way of appending a standard string to
the end of each outbound mail sent via sendmail ? (so I can warn people
against sending in 2.5MB attachments . . . I'm sure there's a way of
deleting them from the pop server without retrieving them. I don't really
want to just leave them on the gofree server . . . for the obvious reasons)

Thanks,
	John.

Oh, yeah, one last thing . . . . anybody know next wednesdays winning lotto
numbers ?