On Wed, 5 May 2004, Alan J. Flavell wrote:
> I've now started rejecting mails which have null envelope senders and
> are addressed to some of these "receive-only" addresses,
I'm asked in email to say more specifically how I'm doing this.
Perhaps it might be of interest also to others, hence I'm replying
to the list, although it's straightforward enough really.
It's in the RCPT ACL, like this:
deny senders = :
hosts = +rbl_hosts
message = This address does not send mail; nondelivery \
reports are rejected as fakes.\n\
SORRYTEXT
recipients = www@??? : help@???
Whereby our addresslist +rbl_hosts defines - more or less - all
non-local hosts (it defines the list of hosts to which RBL checks are
applied, and gets used in a lot of ACL recipes); and the macro
SORRYTEXT is our generic boilerplate which says sorry you've been
inconvenienced by this anti-spam measure and if you can't solve the
problem then you can still contact our postmaster address.
Of course, the list of recipient addresses can be an external flat
file, .db database, whatever you find convenient. If the list is
static then maybe putting it explicitly in the config file is
incrementally more efficient, but it means that any changes to the
list then need exim to be restarted.
