Postfix Architecture OverviewThe queue manager (the qmgr(8) server process in the figure) is the heart of Postfix mail delivery. It contacts the smtp(8), lmtp(8), local(8), virtual(8), pipe(8), discard(8) or error(8) delivery agents, and sends a delivery request for one or more recipient addresses. The discard(8) and error(8) delivery agents are special: they discard or bounce all mail, and are not shown in the figure above.
Postfix Connection Cache
Postfixの運用・管理
