Install FTP server

How to install and setup ftp server

aptitude install vsftpd

Configure access
vim /etc/vsftpd.conf
uncoment line

restart service
systemctl restart vsftpd.service

Configure SSH chroot
vim /etc/ssh/sshd_config

upadate config file like this
#Subsystem sftp /usr/lib/openssh/sftp-server
Subsystem sftp internal-sftp

append to the end of file
Match Group sftp_users
ChrootDirectory /var/www/
AllowTCPForwarding no
X11Forwarding no
ForceCommand internal-sftp

Create user account
adduser ftp-user

Create group sftp_users
groupadd sftp_users

Add users to group
usermod -G sftp_users ftp-user

Restart SSH
systemctl restart vsftpd.service

Set home directory for user
vim /etc/passwd

Check for correct permission and you're good to go.