How can I configure exim4 (or another MTA) to avoid sending duplicate emails?
For my purposes a duplicate email can be defined as: same recipient and subject (or same recipient, subject and body)
I want to ensure only a maximum of 1 of these is sent per 24 hours. Any others should not even be queued.
Is this possible with exim4? If not, what's the best way of going about it?
This is for a safeguard against application bugs.