Against Exim 4.10, at
http://members.cox.net/~kpfleming/exim/callout-cache-patch-v2
Changes since version 1:
- minor code cleanups
- fixed bug where "callout_negative_expire" option was non-functional
- changed database keys to always use lowercased domain part to reduce
extraneous entries
- added additional modifier for ACL to disable caching. You can now specify:
deny hosts = ...
! verify = sender/callout/callout_no_cache
to get standard callout behavior but without records being put into the
cache (I'm using this at the moment for Yahoo! Groups, since the sender
addresses are always unique).