step1 修改/etc/ssh/sshd_config
vim /etc/ssh/sshd_config
#Port 22 //这行去掉#号
Port 8722 //下面添加这一行
阿里云的centos7系统
(不用centos6因为升级内核什么的各种问题和坑)
centos6.5 cpu 1核 内存1GB(腾讯云)
wget https://dl.fedoraproject.org/pub/epel/epel-release-latest-6.noarch.rpm
wget https://centos6.iuscommunity.org/ius-release.rpm
rpm -ivh epel-release-latest-6.noarch.rpm
rpm -ivh ius-release.rpm