[EXIM] Problem with header rewrite option q

I've always had the header rewrite rule
    *@*.dpmms.cam.ac.uk $1@??? bcfrF
to hide our machine names from the world.
However fro time to time I get mail from the machines telling me that
thing have gone wrong and of course the rewritten header has tried to hide
the machine it came from.

So I inserted another rule, giving me:
    root@*.dpmms.cam.ac.uk root@??? bcrq
    *@*.dpmms.cam.ac.uk $1@??? bcfrF

 /usr/lib/exim -C testconfig -brw root@???
  sender: root@???
    from: root@???
      to: root@???
      cc: root@???
     bcc: root@???
reply-to: root@???
env-from: root@???
  env-to: root@???

So the from and env-from lines have still been rewritten :-(.

If I comment out the original rule I get what I wanted
 /usr/lib/exim -C testconfig -brw root@???
  sender: root@???
    from: root@???
      to: root@???
      cc: root@???
     bcc: root@???
reply-to: root@???
env-from: root@???
  env-to: root@???

but of course other users aren't being rewritten at all.

Have I misunderstood the "q" in the rewrite rule (if this rule matches
don't apply any others), or is this a bug in Exim version 1.926 ?

Thanks,

Dr. Andrew C. Aitchison        Computer Officer, DPMMS, Cambridge
A.C.Aitchison@???    http://www.dpmms.cam.ac.uk/~werdna

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