This consists of three parts:

  • setting up an sftp site on EC2
  • creating a new user account
  • configuring the new user account to do read-only ftp, with no ssh privileges

This is intended for transferring files to and from trusted users. I use this as an adequate solution for occasionally sending very large files to clients, using an EC2 instance dedicated to that task. After the transfer is complete, I shut down or delete the instance.

Set up a server using Amazon Web Services EC2, choosing an Ubuntu Amazon Machine Image (AMI). (You can find an AMI using You may want to choose one that’s free tier eligible, such as ami-1aad5273)

ssh into the server:

ssh -i keyfile.pem [email protected]

Install vsftpd:

sudo apt-get install vsftpd

Create a new user:

sudo adduser newusername

Using the AWS Management Console, generate a new key pair for the third-party user.

On Linux, you can generate the public and private keys with the following command on your own local system:

ssh-keygen -b 1024 -f newusername -t dsa

On the server, create the .ssh directory for the new user:

sudo mkdir /home/newusername/.ssh

Paste the public key into /home/newusername/.ssh/authorized_keys.

Set permissions:

sudo chmod 700 /home/newusername/.ssh

sudo chmod 600 /home/newusername/.ssh/authorized_keys

sudo chown -R newusername:newusername /home/newusername/.ssh

Test the new user’s sftp login from your local machine:

sftp -o IdentityFile=newkeypair1.pem [email protected]

Make a new group for users who should be limited to using only sftp:

sudo groupadd sftponly

sudo adduser newusername sftponly

Edit /etc/ssh/sshd_config and change the Subsystem line to:

Subsystem sftp internal-sftp

and add these lines to the end of /etc/ssh/sshd_config:

Match group sftponly
ChrootDirectory /home/%u
X11Forwarding no
AllowTcpForwarding no
ForceCommand internal-sftp

Set permissions, without clobbering files necessary for EC2’s key-based authentication (only download):

sudo chown root:root /home/newusername

To deny SSH shell access, run the following command:

sudo usermod newusername /bin/false

If you want permit uploads use the command below.

sudo chown newusername:newusername /home/newusername


sudo chown -R newusername:newusername /home/newusername/.ssh

sudo /etc/init.d/ssh restart

Now the new user can connect by sftp, but not by ssh. Place the files you want to share in /home/newusername, and share the key with the user or upload your files.