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

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