删除、关闭、打开各自系统的无用附件、防火墙、端口及规则

#### Ubuntu系统下：

开放所有端口

iptables -P INPUT ACCEPT

iptables -P FORWARD ACCEPT

iptables -P OUTPUT ACCEPT

iptables -F

Ubuntu镜像默认设置了Iptable规则，关闭它

apt-get purge netfilter-persistent

reboot

或者强制删除

rm -rf /etc/iptables && reboot

#### Centos系统下：

删除多余附件

systemctl stop oracle-cloud-agent

systemctl disable oracle-cloud-agent

systemctl stop oracle-cloud-agent-updater

systemctl disable oracle-cloud-agent-updater

停止firewall

systemctl stop firewalld.service

禁止firewall开机启动

systemctl disable firewalld.service