Setting up SFTP server in Linux Ubuntu. Command line instructions

Simple step-by-step command line instructions on setting up SFTP server in Ubuntu 12.04, based on http://www.thegeekstuff.com/2012/03/chroot-sftp-setup/ article.

1. Add 'sftpusers' group:

sudo groupadd sftpusers

2. Create a home directory for 'guestuser' user that will be added at the next step:

sudo mkdir /var/guestuserhomedir

As the result of the above command permissions for /var/guestuserhomedir should be 755 (owner: root, group: root).

3. Create 'guestuser' user, add it to the 'sftpusers' group and set a new password for this user:

sudo useradd -g sftpusers -d /var/guestuserhomedir -s /usr/sbin/nologin guestuser
sudo passwd guestuser

4. Create SFTP directories and set permissions (correct permissions are important):

sudo mkdir /var/sftp_upload_dir
sudo mkdir /var/sftp_upload_dir/guestuser
sudo mkdir /var/sftp_upload_dir/guestuser/incoming
sudo chown guestuser:sftpusers /var/sftp_upload_dir/guestuser/incoming
sudo chmod 777 /var/sftp_upload_dir/guestuser/incoming

As the result permissions for /var/sftp_upload_dir and /var/sftp_upload_dir/guestuser directories should be 755 (owner: root, group: root), permissions for /var/sftp_upload_dir/guestuser/incoming should be 777 (owner: guestuser, group: sftpusers).

5. Open /etc/ssh/sshd_config file and comment out the following line:

# Subsystem       sftp    /usr/libexec/openssh/sftp-server

Now add the new line after the commented out line:

Subsystem       sftp    internal-sftp

Add the following lines at the bottom of the file:

Match group sftpusers
ChrootDirectory /var/sftp_upload_dir/%u
ForceCommand internal-sftp

6. Restart SSH service:

sudo /etc/init.d/ssh restart

7. Now you can connect to SFTP server using any client of your choice (FileZilla, Midnight Commander), using the username 'guestuser' and password that you have set at step 3. You will have to use the same port as for SSH (22 by default). You will have full access to incoming directory on the server.