搭建vstftp server
引用：
https://www.jianshu.com/p/91c7d4a115e0
1.安装：
sudo apt-get install vsftpd
2.配置：vim /etc/vsftpd.conf
# Uncomment this to allow local users to log in. # 允许本地用户登陆 local_enable=YES
# You may restrict local users to their home directories. See the FAQ for # the possible risks in this before using chroot_local_user or # chroot_list_enable below. # 禁止用户切换上级目录，并允许ftp根目录有写权限 chroot_local_user=YES allow_writeable_chroot=YES
# This string is the name of the PAM service vsftpd will use.
pam_service_name=vsftpd
# 设定ftp server根目录，
local_root=/tftpboot/
3.nologin无法登陆的原因分析：
vim /etc/pam.d/vsftpd
auth required pam_shells.so 配置项的含义为仅允许用户的shell为 /etc/shells
文件内的shell命令时，才能够成功