[Exim] SMTP callback on envelope sender only

It is my understanding that when you enable SMTP callback, it is done on
both the envelope sender and the header sender.

I'm having problems due to mails coming from other intranets with reports
that do not need replies but that do contain a header from that only
resolves inside their intranet.
I can think of other examples where the domain resolves outside (no split
DNS), but the IP is unreachable, thus SMTP callback fails, and delays the
mail 5 days or more since the failure is temporary and the other side
retries until failure.

Unless I'm mistaken headers_sender_verify only influences the verification
of the domain in the address, not SMTP callback.

Is that correct?
If so, is my resort for now to turn off SMTP callback until exim 4 comes
out?
(IIRC its very granular ACL checks should allow lots of things, including
SMTP callback on the envelope and header sender independently)

Thanks,
Marc
-- 
Microsoft is to operating systems & security ....
                                      .... what McDonalds is to gourmet cooking

Home page: http://marc.merlins.org/ | Finger marc_f@??? for PGP key