If target host have more than one MX, and all they are listed in
/etc/exim/hosts-that-reject-dialups, Exim crashes with "Segmentation fault"
message, both when doing real delivery and when testing with -bt option.
Exim does not crash if target host have only one MX, it does that it should:
it passes message to next router.
This bug is reproduceable. Debug log files can be send upon request.