Re: [exim] Recipients with no MX record need to drop

We realize that. We own the server & control all of the domains on it. We
have some wildcard DNS entries (A Record) that we serve up related search
pages on. The problem is there is no MX record for the wildcarded domains.
In fact, we are trying to break delivery to sites with an A, but no MX
record. We are trying to drop the 100-150000 emails that go nowhere every
day. Exim is crushing that box because of this traffic.
The problem with the mx_domains is the need to continually update it as we
add more domains to the box that might operate this same way. It is easier
for us to maintain the DNS entries properly.

Does anyone know how we can set the ACL to drop anything that doesn't have
the MX record?

On Tue, Nov 11, 2008 at 5:06 PM, Phil Pennock <exim-users@???>wrote:

> On 2008-11-11 at 16:53 -0500, Don Sceifers wrote:
> > As you know, today we saw Exim trying to accept emails for sites hosted
> on
> > cPanel. One example was mary.little@??? which is clearly not a
> > valid email address. We came to the conclusion that Exim was looking up
> an A
> > Record if no MX Record existed.
>
> Because that's the behaviour mandated by the SMTP RFCs.
>
> > What we would like to do is to drop connections for Recipients whose
> domains
> > do not have an MX record. In other words, we just want to drop people
> trying
> > to deliver to mary.little@??? because we would never want to
> see
> > those emails. They are certainly trash to us.
>
> If you do this for all domains then you'll break your ability to deliver
> mail to remote sites where there is just an A record, not an MX record.
>
> Instead look at setting the mx_domains option on your dnslookup router
> to specify a list of domain-matching items (eg: *.co.com : *.com.com )
> which require an MX record.
>
> See The Exim Specification, section 17 (The dnslookup router).
>
> -Phil
>