1：卸载sendmail
cd /usr/ports/mail/sendmail
make deinstall
make clean
2:安装postfix
cd /usr/ports/mail/postfix
make config #开启pcre，SASL2，BDB etc..
make install clean
安装时候会同时安装cyrus-sasl2库，选择配置时候选上BDB等..
安装时还会提示是否替换系统默认的mail程序，此处替换，因为已经卸载sendmail
Would you like to activate Postfix in /etc/mail/mailer.conf [n]? Y
3:如果没有提示安装cyrus-sasl2库，则需要自己手动安装，配置同上图
cd /usr/ports/security/cyrus-sasl2
make install clean
4.安装cyrus-sasl2-saslauthd程序，选择配置时候选上BDB
cd /usr/ports/security/cyrus-sasl2-saslauthd
make install clean
添加一个系统用户 test，测试认证是否正常
testsaslauthd -u test -p pasword 命令测试时,失败提示: 0:NO “authentication failed” 成功则提示0: OK “Success.”
安装完成后加入启动项
ee /etc/rc.conf
加入
saslauthd_enable=”YES”
postfix_enable=”YES”
5.编辑/usr/local/etc/postfix/main.cf 最下面加入
#本机邮件服务器域名，在域名里做一下mx解析，指向本机的公网ip，避免被识别为垃圾
myorigin = mail3.me.com
#开启smtp
smtpd_sasl_auth_enable = yes
broken_sasl_auth_clients = yes
#白名单ip，可以不用验证密码
mynetworks = 168.100.189.0/28, 127.0.0.0/8
smtpd_recipient_restrictions = permit_mynetworks permit_inet_interfaces permit_sasl_authenticated permit_mx_backup reject_unauth_destination
smtpd_client_restrictions = permit_sasl_authenticated
smtpd_sasl_local_domain = $myhostname
6.打开目录 /usr/local/lib/sasl2/里面有个Sendmail.conf，重要！
cp Sendmail.conf smtpd.conf
生成/etc/aliases.db,运行 重要！
newaliases
