# db_load -T -t hash -f virtual-users.txt /etc/vsftpd/virtual-users.db

2. Virtual users and authentication

We are going to use pam_userdb to authenticate the virtual users. This needs a username / password file in `db’ format – a common database format. We need `db_load’ program. For CentOS, Fedora, you may install the package `db4-utils’:

  # yum install db4-utils

For Ubuntu,

  # apt-get install db4.2-util

To create a `db’ format file, first create a plain text file `virtual-users.txt’ with the usernames and passwords on alternating lines:

  mary
  123456
  jack
  654321

Then execute the following command to create the actual database:

  # db_load -T -t hash -f virtual-users.txt /etc/vsftpd/virtual-users.db

Now, create a PAM file /etc/pam.d/vsftpd-virtual which uses your database:

  auth required pam_userdb.so db=/etc/vsftpd/virtual-users
  account required pam_userdb.so db=/etc/vsftpd/virtual-users

3. Configuration of VSFTPD

Create a configuration file /etc/vsftpd/vsftpd-virtual.conf,

<file "conf" "/etc/vsftpd/vsftpd-virtual.conf">
# disables anonymous FTP
anonymous_enable=NO
# enables non-anonymous FTP
local_enable=YES
# activates virtual users
guest_enable=YES
# virtual users to use local privs, not anon privs
virtual_use_local_privs=YES
# enables uploads and new directories
write_enable=YES
# the PAM file used by authentication of virtual uses
pam_service_name=vsftpd-virtual
# in conjunction with 'local_root',
# specifies a home directory for each virtual user
user_sub_token=$USER
local_root=/var/www/virtual/$USER
# the virtual user is restricted to the virtual FTP area
chroot_local_user=YES
# hides the FTP server user IDs and just display "ftp" in directory listings
hide_ids=YES
# runs vsftpd in standalone mode
listen=YES
# listens on this port for incoming FTP connections
listen_port=60021
# the minimum port to allocate for PASV style data connections
pasv_min_port=62222
# the maximum port to allocate for PASV style data connections
pasv_max_port=63333
# controls whether PORT style data connections use port 20 (ftp-data)
connect_from_port_20=YES
# the umask for file creation
local_umask=022
</file>

4. Creation of home directories

Create each user’s home directory in /var/www/virtual, and change the owner of the directory to the user `ftp’:

  # mkdir /var/www/virtual/mary
  # chown ftp:ftp /var/www/virtual/mary

5. Startup of VSFTPD and test
Now we can start VSFTPD by the command:

  # /usr/sbin/vsftpd /etc/vsftpd/vsftpd-virtual.conf

and test the FTP access of a virtual user:

  # lftp -u mary -p 60021 192.168.1.101

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