> The Exim 4 spec says that the "warn" command in an ACL causes a header > line to be added. I think the default text is the same as for Exim 3,
> but I can't actually remember offhand.
It was suggested that a message statement in a warn ACL specified the wording of the
header line. I can't see that in the spec, so is that the case?
i.e. warn message X-RBL-Warning: $sender_host_address is listed by $dnslist_domain
would put that text as the header?
> > A subsidiary question, for Exim4, is: If a "warn dnslist ..."
> > statement in an ACL adds an X-RBL-Warning: header, can routers doing a
> > verify for a subsequent verify statement in the same ACL see that
> > header?
> In the same ACL, no.
>
> > If not, at what stage can Exim check for them?
>
> Header lines added at RCPT time can be seen in an ACL at DATA time.
>
> > What I am planning is for users to opt in to spam rejection on a
> > individual basis, so I want a router to check for the presence of the
> > header and the user's name in the opt-in list.
>
> I'm not sure why you want the routers to be involved in this. Why not
> just do the check in the ACL?
I had not thought I could do that. What I want is for users to be able to opt,
individually, to either ignore RBL checking, divert messages with RBL warning
headers into one of their folders or discard such messages. Though ACLs can have
condition statements, it is too early to check recipients because aliasing, etc. has
not happened and I can't see who the recipient users are.
Ideally, in the discard case I would have made the response to the RCPT command a
550 rejection. That is why I wanted to detect the warning header in the verify
routers in the same ACL. If I can only see the added header in the next ACL then I
could only reject at the DATA stage, which is too late (not all recipients would
want to reject). It appears that what I need is an ACL that is applied before the
first RCPT command has been received.
Rather like the .forward file, I plan on the presence of a file called .spam_divert
to be picked up by a router to route to a suitable appendfile transport to deliver
to the folder. The presence of a file called .spam_reject would route to an
appendfile transport with /dev/null.
Phil.
---------------------------------------
Phil Chambers (postmaster@???)
University of Exeter
