默认系统只运行一个Postfix(MTA)，它监听在25端口，有时我们需要运行多一个postfix，假设让它监听在225端口上，本笔记虽然是在FreeBSD系统上测试通过，其中多数内容也适合各个Linux发行版本以及各个BSD分支，在其他系统上只需要做少量调整。
cp -rp /usr/local/etc/postfix /usr/local/etc/postfixsecend vi /usr/local/etc/postfixsecend/main.cf change: queue_directory = /var/spool/postfix to: queue_directory = /var/spool/postfixsecend :wq mkdir /var/spool/postfixsecend postfix -c /usr/local/etc/postfixsecend check vi /usr/local/etc/postfix/main.cf add: alternate_config_directories = /usr/local/etc/postfixsecend :wq vi /usr/local/etc/postfixsecend/main.cf add: inet_interfaces = 202.181.206.235 :wq vi /usr/local/etc/postfix/main.cf add: smtp_bind_address = 202.181.206.234 :wq vi /etc/services add: smtp2 225/tcp mail #Simple Mail Transfer smtp2 225/udp mail #Simple Mail Transfer :wq vi /usr/local/etc/postfixsecend/master.cf change: smtp inet n - n - - smtpd to: smtp2 inet n - n - - smtpd :wq postfix -c /usr/local/etc/postfixsecend start