https://www.vultr.com/docs/how-to-configure-ufw-firewall-on-ubuntu-14-04
官方文档
https://help.ubuntu.com/community/UFW
查看开放端口
sudo netstat -nupt -l
https://www.vultr.com/docs/how-to-configure-ufw-firewall-on-ubuntu-14-04
https://help.ubuntu.com/community/UFW
sudo netstat -nupt -l
让时间为你证明