FTP với virutal user

Install vsftp

Run the following command in terminal to install vsftpd package:

[root@ftp ~]# yum install vsftpd ftp -y

Start the vsftpd service and make it to start automatically on every reboot:

[root@ftp ~]# service vsftpd start
Starting vsftpd for vsftpd:                                [  OK  ]
[root@ftp ~]# chkconfig vsftpd on

Configure vsftpd

Open the vsftpd configuration file /etc/vsftpd/vsftpd.conf. Find the following lines and make the changes as shown below:

[root@ftp ~]# vi /etc/vsftpd/vsftpd.conf
 [...]
## Set to "NO" ##
anonymous_enable=NO

## Uncomment ##
ascii_upload_enable=YES
ascii_download_enable=YES

## Uncomment - Enter your Welcome message - This is optional ##
ftpd_banner=Welcome to UNIXMEN FTP service.

## Add at the end of this  file ##
use_localtime=YES

Restart vsftpd service:

[root@ftp ~]# service vsftpd restart
Shutting down vsftpd:                                      [  OK  ]
Starting vsftpd for vsftpd:                                [  OK  ]

Create FTP users

By default, root user is not allowed to login to ftp server for security purpose. So let us create a testing user called “sk” with password “centos”:

[root@ftp ~]# useradd sk
[root@ftp ~]# passwd sk
Changing password for user sk.
New password:
BAD PASSWORD: it is based on a dictionary word
BAD PASSWORD: is too simple
Retype new password:
passwd: all authentication tokens updated successfully.

Connecting to FTP server

Now let us try to connect to FTP server itself with user “sk”:

[root@ftp ~]# ftp 192.168.1.200
Connected to 192.168.1.200 (192.168.1.200).
220 Welcome to UNIXMEN FTP service.
Name (192.168.1.200:root): sk
331 Please specify the password.
Password:
500 OOPS: cannot change directory:/home/sk
Login failed.
ftp>

Probably you will get an error like “500 OOPS: cannot change directory”.

This is because your SELinux restricts the user to login to ftp server. So let us update the SELinux boolean values for FTP service:

[root@ftp ~]# setsebool -P ftp_home_dir on

Now try again to login to FTP server:

[root@ftp ~]# ftp 192.168.1.200
Connected to 192.168.1.200 (192.168.1.200).
220 Welcome to UNIXMEN FTP service.
Name (192.168.1.200:root): sk
331 Please specify the password.
Password:
230 Login successful.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp>

Now you will be able to login to FTP server without any problems.

Install Berkeley Database(db4)

In this method, we use Berkeley database(db4(version4) to store virtual user names with their passwords. First install db4-utils package if it not installed:

[root@ftp ~]# yum install db4-utils db4 -y

Create database file for virtual users

First create a plain text file and enter the virtual user names and their passwords one by one. Then create the db file from the plain text file.

For instance, i create a plain text file called virtual_users.txt in /home directory with username senthil and password centos:

[root@ftp ~]# vi /home/virtual_users.txt
senthil
centos

Save and exit the file. Run the following command to create database file:

[root@ftp ~]# db_load -T -t hash -f /home/virtual_users.txt /etc/vsftpd/virtual_users.db

Here virtual.db is the actual database file for virtual users.

Create a PAM file

Now create a PAM file to use the database virtual_users.db which we created from the plain text file. Add the following lines:

[root@ftp ~]# vi /etc/pam.d/vsftpd_virtual
#%PAM-1.0
auth    required        pam_userdb.so   db=/etc/vsftpd/virtual_users
account required        pam_userdb.so   db=/etc/vsftpd/virtual_users
session required        pam_loginuid.so

Save and exit the file.

vsftpd configuration

Make sure that you have added or edited the following lines in the vsftpd.conf file:

[root@ftp ~]# vi /etc/vsftpd/vsftpd.conf

# Allow anonymous FTP? (Beware - allowed by default if you comment this out).
anonymous_enable=NO

# Uncomment this to allow local users to log in.
local_enable=YES

## Enable virtual users
guest_enable=YES

## Virtual users will use the same permissions as anonymous
virtual_use_local_privs=YES

#
# Uncomment this to enable any form of FTP write command.
write_enable=YES

## PAM file name
pam_service_name=vsftpd_virtual

## Home Directory for virtual users
user_sub_token=$USER
local_root=/ftp/virtual/$USER

# You may specify an explicit list of local users to chroot() to their home
# directory. If chroot_local_user is YES, then this list becomes a list of
# users to NOT chroot().
chroot_local_user=YES

## Hide ids from user
hide_ids=YES

Save and exit the file.

Now create home directories for virtual users:

[root@server ~]# mkdir -p /ftp/virtual/senthil
[root@server ~]# chown -R ftp:ftp /ftp/virtual/senthil/

Start or restart vsftpd service:

[root@ftp ~]# service vsftpd restart
Shutting down vsftpd:                                      [  OK  ]
Starting vsftpd for vsftpd:                                [  OK  ]

Now try to login to FTP server using virtual user senthil with password centos:

[root@ftp ~]# ftp 192.168.1.200
 Connected to 192.168.1.200 (192.168.1.200).
 220 Welcome to UNIXMEN FTP service.
 Name (192.168.1.200:root): senthil
 331 Please specify the password.
 Password:
 230 Login successful.
 Remote system type is UNIX.
 Using binary mode to transfer files.
 ftp>

Now you will able to login to FTP server.

Verify the log files using the following command:

[root@ftp ~]# tail -f /var/log/secure
Jun  3 17:23:35 ftp vsftpd[1945]: pam_userdb(vsftpd_virtual:auth): user 'senthil' granted access

- See more at: http://www.unixmen.com/install-vsftp-with-virtual-users-on-centos-rhel-scientific-linux-6-4/#sthash.DMsNwHgj.dpuf