Maybe this section of the docs is what you are trying to accomplish ? http://www.postfix.org/TUNING_README.html#rope
-ANGELO FAZZINA ang...@uconn.edu University of Connecticut, ITS, SSG, Server Systems 860-486-9075 -----Original Message----- From: owner-postfix-us...@postfix.org <owner-postfix-us...@postfix.org> On Behalf Of Zsombor B Sent: Thursday, November 5, 2020 8:12 AM To: postfix-users@postfix.org Subject: limiting connections to a single host *Message sent from a system outside of UConn.* Hi, I have to relay mails to a mail gateway that often rejects connections because we are too pushy. The admin of that service suggested us to open X connections and send Y messages per connection. How can I set this up either for one specific destination or to all? Thanks in advance, Zsombor