防火墙

# 查看防火墙状态
systemctl status firewalld

# 开启防火墙
systemctl start firewalld

# 关闭防火墙
systemctl stop firewalld

# 开机自启
systemctl enable firewalld

# 禁止开机自启
systemctl disable firewalld

# 配置防火墙规则
firewall-cmd --zone=public --add-port=22/tcp --permanent
firewall-cmd --reload