How to install a FTP Server with ProFTPD (Debian/Ubuntu)?

In this tutorial, we will see how to install an FTP server on our Linux VPS. The tutorial is Debian and Ubuntu compatible.

All the following commands must be executed with the root user.

Installation of the package

The installation of proftpd requires only a simple command through the package manager:

apt install proftpd-basic

Configuration

The default configuration is valid, nevertheless it is necessary to check several points in the file /etc/proftpd/proftpd.conf:

First of all, you have to make sure that the users are chrooted in their user directory, so that they can't walk around on the whole system, with the option :

DefaultRoot ~

Second, setting up passive ports can allow customers having problematic routers to use ports that are usually well unlocked on the way out:

PassivePorts 60000 65534

Virtual user management

By default, authentication is done with Unix users only (= system users).

It is advisable to set the authentication by virtual users, for a more flexible management. In the /etc/proftpd/proftpd.conf, check that these lines are not commented. If they are not present, add them.

AuthUserFile          /etc/proftpd/ftpd.passwd
AuthOrder         mod_auth_file.c

Then check that the value RequireValidShell = off is well present, and not commented.

We will now initialize the file ftpd.passwd which proftpd will then use to store the information of FTP users.

touch /etc/proftpd/ftpd.passwd
chmod 440 /etc/proftpd/ftpd.passwd

The configuration is finished, you just have to restart the proftpd service:

service proftpd restart

Add users

The addition of an FTP user is done with the following command.

Replace

  • LOGIN by the username of the FTP account (ex: jdoe).
  • UID by the UID of the system user account to which the FTP account belongs (to find the UID of a linux account, id nomdeluser, for example id root).
  • GID by GID of the group of the system user account to which the FTP account belongs (to find the GID of a linux account, id nomdeluser, for example id root).
  • /PATH/TO/HOME by the path of the directory to which the FTP account will have access.

To learn more about how to retrieve a user's UID and GID, see the following tutorial: [How to find a user's UID or GID(https://mtxserv.com/vps-server/doc/how-to-find-the-uid-or-gid-of-a-linux-user).

ftpasswd --passwd --file=/etc/proftpd/ftpd.passwd --name=LOGIN --uid=UID --gid=GID --home=/PATH/TO/HOME --shell=/bin/false

To avoid prompting for the password, you can use the --stdin option as follows:

echo "PASSWORD" | ftpasswd --passwd --stdin --file=/etc/proftpd/ftpd.passwd --name=LOGIN --uid=UID --gid=GID --home=/PATH/TO/HOME --shell=/bin/false

Change user password

The modification is done by the following command:

ftpasswd --passwd --file=/etc/proftpd/ftpd.passwd --change-password --name=LOGIN

To avoid prompting the password, you can use the --stdin as follows:

echo "MOTDEPASSE" | ftpasswd --passwd --file=/etc/proftpd/ftpd.passwd --change-password --name=LOGIN --stdin

Deleting a user

To delete a user, use the following command:

ftpasswd --passwd --file=/etc/proftpd/ftpd.passwd --delete-user --name=LOGIN

Shell verification bug

In case of invalid shell problem related to the use of user there are 2 possible solutions.

  • Either disable shell checking: RequireValidShell off
  • Either add to the file /etc/shells : /bin/false

For the sake of cleanliness, prefer the second solution :-)