安装：

apt install ufw

 
启用和删除：

ufw enable
ufw status numbered
ufw delete (数字)
ufw delete allow 22
ufw delete allow ssh
ufw status verbose

添加规则：

ufw default deny incoming
ufw default allow outgoing
ufw allow 22
ufw allow ssh
ufw allow 1000:2000/tcp
ufw allow from 192.168.0.2
ufw allow from 192.168.0.2 to any port 22
ufw allow from 192.168.0.0/24
ufw allow in on eth0 to any port 22