Re: [Exim] Frozen messages with null envelope sender

On Sun, 7 Mar 2004, Steffen Heil wrote:

> Is there a way to drop messages instead to freeze them, if (and only if)
> they have null envelope senders?

With respect, are you sure that's the right question? ...

> I have lots of these mails, as everyone will, because of virii using forged
> addresses.

Are you talking about forged valid addresses, or forged invalid
addresses?

If the addresses are invalid, then reject the items at RCPT time (use
call-forward if you're a relay MTA and don't know what addresses are
valid at the ultimate hosts - we may assume you're on good terms with
the management of those hosts and their admins can accommodate the
requirement to respond decently to callouts from the relaying MTA).

If they get past that test, then - with us - they still have to get
past TimJ's spamassassin rules that are intended to block "bogus virus
alerts" (BVAs).

We do get a modest number of bounces for valid addresses. But the
normal procedure for those would be simply to deliver them to the
recipient, and leave them to work out what they mean. However, on a
mailer of the scale of our departmental mailer, we can afford to
freeze those bounces which get past our other tests. The postmasters
then quickly eyeball them and either pass them for delivery or discard
them. And possibly tune the rules so that particular patterns of
bounce are delivered directly to the recipients in future; or rejected
as BVAs, as appropriate.

That procedure wouldn't be acceptable in other situations, for sure,
but in the interests of a reliable mail system I am very reluctant to
silently discard anything on an automated basis: items should either
be delivered or positively rejected IMHO, and - except maybe in
abnormal situations which generated thousands of spurious bounces -
only discarded after manual intervention.

all the best