1.  在CENTOS上安装iRedMail ，非常简单
wget https://bitbucket.org/zhb/iredmail/downloads/iRedMail-0.9.5-1.tar.bz2
tar xjf iRedMail-0.9.5-1.tar.bz2
cd iRedMail-0.9.5-1
setenforce 0
IREDMAIL_EPEL_MIRROR='http://mirrors.aliyun.com/epel'
IREDMAIL_MIRROR='http://42.159.241.31'  bash iRedMail.sh

2. 在REDHAT上安装iRedMail ，要先改一下YUM,否则安装不了，因为没有注册REDHAT，官方的yum不能用。
安装办法如下：
卸载原来的yum
rpm -qa|grep yum
rpm -qa|grep yum|xargs rpm -e --nodeps

下载centos 的yum相关包及RPM-GPG-KEY-CentOS-6文件
http://mirror.centos.org/centos/6/os/x86_64/
http://mirror.centos.org/centos/6/os/x86_64/RPM-GPG-KEY-CentOS-6

安装centos的yum
rpm -ivh yum-3.2.29-40.el6.centos.noarch.rpm yum-metadata-parser-1.1.2-16.el6.x86_64.rpm yum-plugin-fastestmirror-1.1.30-14.el6.noarch.rpm  

复制RPM-GPG-KEY-CentOS-6到redhat上/etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6（也可找一台CentOS复制该文件）
cp RPM-GPG-KEY-CentOS-6  /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6

vim /etc/yum.repo.d/CentOS-Base.repo
替换所有的 release=$releasever 为  release=6

wget https://bitbucket.org/zhb/iredmail/downloads/iRedMail-0.9.5-1.tar.bz2
tar xjf iRedMail-0.9.5-1.tar.bz2
cd iRedMail-0.9.5-1
setenforce 0
IREDMAIL_EPEL_MIRROR='http://mirrors.aliyun.com/epel'
IREDMAIL_MIRROR='http://42.159.241.31'  bash iRedMail.sh

步骤参考： http://www.iredmail.com/docs/install.iredmail.on.rhel.html

安装的账号信息：
cat /root/soft/iRedMail-0.9.5-1/iRedMail.tips

foxmail outlook配置：
POP3: 192.168.1.111   995  （勾选SSL
SMTP:192.168.1.111    587  (不能勾选SSL)