Create SFTP server

Create user group

groupadd sftp

Create user

useradd sftpuser
passwd sftpuser
usermod -s /sbin/nologin sftpuser

create data directory

mkdir -p /opt/sftpdata/sftpuser
chwon -R root.sftp /opt/sftpdata/sftpuser

mkdir -p /opt/sftpdata/sftpuser/input
mkdir -p /opt/sftpdata/sftpuser/output

chown -R sftpuser.sftp /opt/sftpdata/sftpuser/input
chown -R sftpuser.sftp /opt/sftpdata/sftpuser/output

config sshd_config

vi /etc/ssh/sshd_config

Port 8000
PasswordAuthentication no
AllowAgentForwarding no
AllowTcpForwarding no
Subsystem sftp internal-sftp

Match Group sftp
    X11Forwarding no
    AllowTcpForwarding no
    ChrootDirectory /opt/sftpdata/%u
    ForceCommand internal-sftp