ftp服务端软件用的是什么?
vsftpd
@任冠宇: 参考 How to create a FTP user with specific /dir/ access only on a Centos / linux installation 中的回答:
chroot_local_user=YES
upload_ftp:x:1001:1001::/var/www/sites/:/bin/bash
usermod -d /var/www/my.domain.example/ exampleuser