i don't know if this is possible.
situation:
i have a device that i have no control over it
in general it behave properly, just the proper amount of email. Port 587 is open for that ip to allow sending email.
problem:
sometime it start sending multiple email per minutes for no reason whatsoever, for now I'm stuck with this thing, i can't fix or disconnect it.
the extra email are useless and not harmful, just annoying like hell
so, question;
how would you limit it to a maximum of 1 email per 3 minutes