实验环境：三台主机，分别为
mail.zbka.com(ip 192.168.18.61/24)网关（192.168.18.1）dns（192.168.18.1）
mail.zbkb.com(ip 172.16.18.61/16) 网关（172.16.18.1） dns（172.16.18.1）
dns.localdomain(eth0 192.168.18.1/24 eth1 172.16.18.1/16)
1. 在mail.zbka.com安装postfix服务，并配置
vim /etc/postfix/main.cf
myhostname = mail.zbka.com
mydomain = zbka.com
myorigin = $mydomain
inet_interfaces = all
mydestination = $myhostname, $mydomain
mynetworks = 192.168.18.0/24, 127.0.0.0/8
relay_domains = $mydestination
service postfix restart
chkconfig postfix on
vim /etc/sysconfig/saslauthd
MECH=shadow
service saslauthd restart
chkconfig saslauthd on
2.设置postfix启用smtp认证
vim /etc/postfix/main.cf
smtpd_sasl_auth_enable = yes
smtpd_sasl_local_domain = ''
smtpd_recipient_restrictions = permit_mynetworks,permit_sasl_authenticated,reject_unauth_destination
broken_sasl_auth_clients = yes
smtpd_client_restrictions = permit_sasl_authenticated
smtpd_sasl_security_options = noanonymous
service postfix restart
3.安装pop服务：dovecot
vim /etc/dovecot.conf
protocols = pop3 pop3s
protocol pop3 {
listen = *:10100
}
service dovecot start
chkconfig dovecot on
4.安装IMAP服务：cyrus-imapd
passwd cyrus //为管理员设置密码
vim /etc/postfix/main.cf
mailbox_transport = lmtp:unix:/var/lib/imap/socket/lmtp
service postfix restart
cyradm -u cyrus localhost //为用户创建邮件信箱
cm user.aaa
cm user.aaa.Send
cm user.aaa.Trash
cm user.aaa.Drafts
setquota user.aaa 5210
5.Web方式收发邮件
安装squirrelmail
/usr/share/squirrelmail/config/conf.pl //打开配置工具
6.同上配置mail.zbkb.com的postfix服务
设置ip为(172.168.18.61/16)
创建用户bbb邮箱
7.配置dns.localdomain服务器
（1）设置(eth0 192.168.18.1/24 eth1 172.16.18.1/16)
（2）echo 1 > /proc/sys/net/ipv4/ip_forward //开启网卡转发
vim /etc/sysctl.conf //永久开启
net.ipv4.ip_forward = 1
（3）配置dns服务
(1)vim named.conf
options {
directory "/var/named";
};
zone "zbka.com" {
type master;
file "zbka.com.zone";
};
zone "zbkb.com" {
type master;
file "zbkb.com.zone";
};
(2)vim zbka.com.zone
@ IN SOA dns root (
20121205 ; serial (d. adams)
3H ; refresh
15M ; retry
1W ; expiry
1D ) ; minimum
zbka.com. IN NS master.zbka.com.
zbka.com. IN MX 10 mail.zbka.com.
mail IN A 192.168.18.61
vim zbkb.com.zone
@ IN SOA dns root (
20121205 ; serial (d. adams)
3H ; refresh
15M ; retry
1W ; expiry
1D ) ; minimum
zbkb.com. IN NS master.zbkb.com.
zbkb.com. IN MX 10 mail.zbkb.com.
mail IN A 172.16.18.61
（4）service named restart //重启服务
（5）vim /etc/resolv.conf //清空dns指向
8.客户端互发邮件测试。
http://mail.zbka.com/webmail
http://mail.zbkb.com/webmail
