CentOS7.x自带firewall防火墙，FTP使用需要开启20 21 22 30000-35000几个端口.
操作命令如下：
firewall-cmd –zone=public –add-port=20/tcp –permanent
firewall-cmd –zone=public –add-port=21/tcp –permanent
firewall-cmd –zone=public –add-port=22/tcp –permanent
firewall-cmd –zone=public –add-port=30000-35000/tcp –permanent
firewall-cmd –zone=public –add-port=20/udp –permanent
firewall-cmd –zone=public –add-port=21/udp –permanent
firewall-cmd –zone=public –add-port=30000-35000/udp –permanent
添加成功后，重启防火墙,即可！
systemctl restart firewalld.service