How to Configure SFTP Server with Chroot in Debian 10
======
**SFTP** stands for Secure File Transfer Protocol / SSH File Transfer Protocol, it is one of the most common method which is used to transfer files securely over ssh from our local system to remote server and vice-versa. The main advantage of sftp is that we don’t need to install any additional package except ‘**openssh-server**’, in most of the Linux distributions ‘openssh-server’ package is the part of default installation. Other benefit of sftp is that we can allow user to use sftp only not ssh.
[![Configure-sftp-debian10][1]][2]
Recently Debian 10, Code name ‘Buster’ has been released, in this article we will demonstrate how to configure sftp with Chroot ‘Jail’ like environment in Debian 10 System. Here Chroot Jail like environment means that user’s cannot go beyond from their respective home directories or users cannot change directories from their home directories. Following are the lab details:
* OS = Debian 10
* IP Address = 192.168.56.151
Let’s jump into SFTP Configuration Steps,
### Step:1) Create a Group for sftp using groupadd command
Open the terminal, create a group with a name “**sftp_users**” using below groupadd command,
```
root@linuxtechi:~# groupadd sftp_users
```
### Step:2) Add Users to Group ‘sftp_users’ and set permissions
In case you want to create new user and want to add that user to ‘sftp_users’ group, then run the following command,
As we have already stated that sftp operations are done over the ssh, so it’s configuration file is “**/etc/ssh/sshd_config**“, Before making any changes I would suggest first take the backup and then edit this file and add the following content,
To make above changes into the affect, restart ssh service using following systemctl command
```
root@linuxtechi:~# systemctl restart sshd
```
In above ‘sshd_config’ file we have commented out the line which starts with “Subsystem” and added new entry “Subsystem sftp internal-sftp” and new lines like,
“**Match Group sftp_users”**–> It means if a user is a part of ‘sftp_users’ group then apply rules which are mentioned below to this entry.
“**ChrootDierctory %h**” –> It means users can only change directories within their respective home directories, they cannot go beyond their home directories, or in other words we can say users are not permitted to change directories, they will get jai like environment within their directories and can’t access any other user’s and system’s directories.
“**ForceCommand internal-sftp**” –> It means users are limited to sftp command only.
### Step:4) Test and Verify sftp
Login to any other Linux system which is on the same network of your sftp server and then try to ssh sftp server via the users that we have mapped in ‘sftp_users’ group.
```
[root@linuxtechi ~]# ssh root@linuxtechi
root@linuxtechi's password:
Write failed: Broken pipe
[root@linuxtechi ~]# ssh root@linuxtechi
root@linuxtechi's password:
Write failed: Broken pipe
[root@linuxtechi ~]#
```
Above confirms that users are not allowed to SSH , now try sftp using following commands,
Let’s try to download a file using sftp ‘**get**‘ command
```
sftp> get devops-actions.txt
Fetching /devops-actions.txt to devops-actions.txt
/devops-actions.txt 100% 155 0.2KB/s 00:00
sftp>
sftp> cd /etc
Couldn't stat remote file: No such file or directory
sftp> cd /root
Couldn't stat remote file: No such file or directory
sftp>
```
Above output confirms that we are able to download file from our sftp server to local machine and apart from this we have also tested that users cannot change directories.
Let’s try to upload a file under “**upload**” folder,
```
sftp> cd upload/
sftp> put metricbeat-7.3.1-amd64.deb
Uploading metricbeat-7.3.1-amd64.deb to /upload/metricbeat-7.3.1-amd64.deb
This confirms that we have successfully uploaded a file from our local system to sftp server.
Now test the SFTP server with winscp tool, enter the sftp server ip address along user’s credentials,
[![Winscp-sftp-debian10][1]][3]
Click on Login and then try to download and upload files
[![Download-file-winscp-debian10-sftp][1]][4]
Now try to upload files in upload folder,
[![Upload-File-using-winscp-Debian10-sftp][1]][5]
Above window confirms that uploading is also working fine, that’s all from this article. If these steps help you to configure SFTP server with chroot environment in Debian 10 then please do share your feedback and comments.
