Setting up SFTP Chroot Directory with NFS Share: IN/OUT Subdirectories
In this article, we will discuss how to set up an SFTP Chroot Directory with NFS Share, specifically for IN and OUT subdirectories. This setup is useful for creating a secure file transfer system for users, where they can only access specific directories on the server.
Prerequisites
Before we begin, make sure you have the following:
- A server running a Unix-like operating system, such as Ubuntu or CentOS.
- NFS server and client packages installed.
- OpenSSH server installed.
Creating NFS Share
First, we need to create an NFS share for the IN and OUT subdirectories. Let's assume that we have a user named "user" and we want to create the NFS share under "/data/user".
# mkdir -p /data/user/IN /data/user/OUT
# chown user:user /data/user/IN /data/user/OUT
# chmod 755 /data/user/IN /data/user/OUT
# echo "/data/user *(rw,sync,no_subtree_check)" > /etc/exports
Then, restart the NFS service to apply the changes.
# systemctl restart nfs-server
Setting up SFTP Chroot Directory
Next, we need to set up the SFTP Chroot Directory for the user. We will create a new group called "sftponly" and add the user to this group.
# groupadd sftponly
# usermod -aG sftponly user
Then, we will modify the SSH configuration to allow SFTP connections and set the ChrootDirectory for the "sftponly" group.
# echo "Match Group sftponly
ChrootDirectory /data/user
ForceCommand internal-sftp" > /etc/ssh/sshd_config.d/sftp.conf
After modifying the SSH configuration, restart the SSH service to apply the changes.
# systemctl restart ssh
Testing the Setup
Now, let's test the setup by connecting to the SFTP server as the "user" and verifying that we can only access the IN and OUT subdirectories.
$ sftp user@server
Connected to server.
Changing to: /
sftp> ls
IN OUT
sftp> cd IN
sftp> ls
file1 file2
sftp> cd ..
sftp> cd OUT
sftp> ls
sftp> quit
References
This article covered the key concepts of setting up an SFTP Chroot Directory with NFS Share for IN and OUT subdirectories. By following the steps outlined in this article, you can create a secure file transfer system for your users, where they can only access specific directories on the server.