https://blog.csdn.net/cc_want/article/details/85337241
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