centos7.9 关闭防火墙和开放指定端口

关闭防火墙
systemctl status firewalld    查看防火墙状态
systemctl stop firewalld    实时关闭防火墙
systemctl disable firewalld    永久禁用防火墙，禁止开机自启动

关闭SELinux
vim /etc/selinux/config
SELINUX=permissive    #修改为disabled
reboot  重启服务器生效

防止客户启动防火墙后导致SSH连不上，对SSH端口31703放行
systemctl start firewalld
firewall-cmd --zone=public --add-port=31703/tcp --permanent
firewall-cmd --reload
systemctl stop firewalld
systemctl disable firewalld

如需关闭防火墙端口放行，则执行下面命令
firewall-cmd --zone=public --remove-port=31703/tcp --permanent