Red Hat / CentOS VSFTPD FTP Server Configuration

Vsftpd (Very Secure FTP Daemon) is an FTP server for UNIX-like systems, including CentOS / RHEL / Fedora and other Linux distributions. It supports IPv6, SSL, locking users to their home directories and many other advanced features.

In this guide you will learn:

1. Setup vsftpd to provide FTP service.
2. Configure vsftpd.
3. Configure Firewalls to protect the FTP server.
4. Configure vsftpd with SSL/TLS.
5. Setup vsftpd as download only anonymous internet server.
6. Setup vsftpd with virtual users and more.

VSFTPD offer security, performance and stability over other servers. A quick list of vsftpd features:

1. Virtual IP configurations
2. Virtual users
3. Run as standalone or inetd / xinetd operation
4. Per-user configuration
5. Bandwidth throttling
6. Per-source-IP configurability
7. Per-source-IP limits
8. IPv6 ready
9. Encryption support through SSL integration
10. And much more.

Install Vsftpd FTP Server

Install the vsftpd package via yum command:
# yum install vsftpd

Vsftpd Defaults

1. Default port: TCP / UDP – 21 and 20
2. The main configuration file: /etc/vsftpd/vsftpd.conf
3. Users that are not allowed to login via ftp: /etc/vsftpd/ftpusers

Configure Vsftpd Server

Open the configuration file, type:
# vi /etc/vsftpd/vsftpd.conf

Turn off standard ftpd xferlog log format:

xferlog_std_format=NO

Turn on verbose vsftpd log format. The default vsftpd log file is /var/log/vsftpd.log:

log_ftp_protocol=YES

Above two directives will enable logging of all FTP transactions. To lock down users to their home directories, edit/append directives as follows:

chroot_local_user=YES

Create warning banners for all FTP users:

banner_file=/etc/vsftpd/issue

Create /etc/vsftpd/issue file with a message compliant with the local site policy or a legal disclaimer:

NOTICE TO USERS

Use of this system constitutes consent to security monitoring and testing.
All activity is logged with your host name and IP address.

Turn On Vsftpd Service

Turn on vsftpd on boot:
# chkconfig vsftpd on
Start the service:
# service vsftpd start
# netstat -tulpn | grep :21

Configure Iptables To Protect The FTP Server

Open file /etc/sysconfig/iptables, enter:
# vi /etc/sysconfig/iptables
Add the following lines, ensuring that they appear before the final LOG and DROP lines for the RH-Firewall-1-INPUT:

-A RH-Firewall-1-INPUT -m state --state NEW -p tcp --dport 21 -j ACCEPT

Open file /etc/sysconfig/iptables-config, enter:
# vi /etc/sysconfig/iptables-config
Ensure that the space-separated list of modules contains the FTP connection tracking module:

IPTABLES_MODULES="ip_conntrack_ftp"

Save and close the file. Restart firewall:
# service iptables restart

Tip: View FTP Log File

Type the following command:
# tail -f /var/log/vsftpd.log
Sample output:

Thu May 21 11:40:31 2009 [pid 42298] FTP response: Client "10.1.3.108", "530 Please login with USER and PASS."
Thu May 21 11:40:36 2009 [pid 42298] FTP command: Client "10.1.3.108", "USER vivekda"
Thu May 21 11:40:36 2009 [pid 42298] [vivek] FTP response: Client "10.1.3.108", "331 Please specify the password."
Thu May 21 11:40:38 2009 [pid 42298] [vivek] FTP command: Client "10.1.3.108", "PASS "
Thu May 21 11:40:38 2009 [pid 42297] [vivek] OK LOGIN: Client "10.1.3.108"
Thu May 21 11:40:38 2009 [pid 42299] [vivek] FTP response: Client "10.1.3.108", "230 Login successful."
Thu May 21 11:40:38 2009 [pid 42299] [vivek] FTP command: Client "10.1.3.108", "SYST"
Thu May 21 11:40:38 2009 [pid 42299] [vivek] FTP response: Client "10.1.3.108", "215 UNIX Type: L8"
Thu May 21 11:40:39 2009 [pid 42299] [vivek] FTP command: Client "10.1.3.108", "PORT 10,1,3,108,162,253"
Thu May 21 11:40:39 2009 [pid 42299] [vivek] FTP response: Client "10.1.3.108", "200 PORT command successful. Consider using PASV."
Thu May 21 11:41:05 2009 [pid 42299] [vivek] FTP response: Client "10.1.3.108", "150 Ok to send data."
Thu May 21 11:41:06 2009 [pid 42299] [vivek] OK UPLOAD: Client "10.1.3.108", "/windows-7-too-many-programs.png", 8957 bytes, 6.70Kbyte/sec
Thu May 21 11:41:06 2009 [pid 42299] [vivek] FTP response: Client "10.1.3.108", "226 File receive OK."
Thu May 21 11:41:10 2009 [pid 42299] [vivek] FTP command: Client "10.1.3.108", "TYPE A"
Thu May 21 11:41:10 2009 [pid 42299] [vivek] FTP response: Client "10.1.3.108", "200 Switching to ASCII mode."
Thu May 21 11:41:11 2009 [pid 42299] [vivek] FTP command: Client "10.1.3.108", "PORT 10,1,3,108,217,96"
Thu May 21 11:41:11 2009 [pid 42299] [vivek] FTP response: Client "10.1.3.108", "200 PORT command successful. Consider using PASV."
Thu May 21 11:41:11 2009 [pid 42299] [vivek] FTP command: Client "10.1.3.108", "LIST"
Thu May 21 11:41:11 2009 [pid 42299] [vivek] FTP response: Client "10.1.3.108", "150 Here comes the directory listing."
Thu May 21 11:41:11 2009 [pid 42299] [vivek] FTP response: Client "10.1.3.108", "226 Directory send OK."

Tip: Restrict Access to Anonymous User Only

Edit the vsftpd configuration file /etc/vsftpd/vsftpd.conf and add the following:

local_enable=NO

Tip: Disable FTP Uploads

Edit the vsftpd configuration file /etc/vsftpd/vsftpd.conf and add the following:

write_enable=NO

Security Tip: Place the FTP Directory on its Own Partition

Separation of the operating system files from FTP users files may result into a better and secure system. Restrict the growth of certain file systems is possible using various techniques. For e.g., use /ftp partition to store all ftp home directories and mount ftp with nosuid, nodev and noexec options. A sample /etc/fstab enter:

/dev/sda5  /ftp          ext3    defaults,nosuid,nodev,noexec,usrquota 1 2

Disk quota must be enabled to prevent users from filling a disk used by FTP upload services. Edit the vsftpd configuration file. Add or correct the following configuration options to represents a directory which vsftpd will try to change into after an anonymous login:
anon_root=/ftp/ftp/pub