1. 配置epel源（exim包位于EPEL软件源中）

CentOS7

1. #cat>/etc/yum.repos.d/epel.repo<<EOF
2. [epel]
3. name=ExtraPackagesforEnterpriseLinux7–\$basearch
4. #baseurl=http://download.fedoraproject.org/pub/epel/7/\$basearch
5. mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-7&arch=\$basearch
6. failovermethod=priority
7. enabled=1
8. gpgcheck=0
9. EOF