The Sender Filter agent relies on the MAIL FROM: Simple Mail Transfer Protocol (SMTP) header to determine what action, if any, to take on an inbound e-mail message.

• 发件人筛选器代理依靠MAIL FROM:简单邮件传输协议(SMTP)邮件头来确定要对入站电子邮件执行的操作(如果有)。