Hello, Thanks to your advices, i manage to put a throttle by domain by adding in my master.cf domain1 unix - - n - - smtp -o smtp_fallback_relay=
in my transport : domain1.tld domain1: and in my main domain1_destination_rate_delay = 60s but i would like to know if there is a way to send for 10 mails with destination rate delay to domain1 equal to 0 then to throttle (so for instance wait 1 min) then 10 mail then wait etc, Thank you for your help :)