Configuring vsftpd: Port Settings, User Authentication, and Virtual User Management

After installing vsftpd and understanding its main configuration file /etc/vsftpd/vsftpd.conf, you can set up a functional FTP service.

Port and basic options

Set the listening port and enable downloads and client limits:

listen_port=21

download_enable=YES

max_clients=100

max_per_ip=100

Disable anonymous login anonymous_enable=NO Real users are discouraged from using FTP because of its plaintext nature; instead, use SFTP.

Active and passive mode configuration

Enable active mode: connect_from_port_20=YES Open firewall for port 21 and allow established connections:

iptables -A INPUT -p tcp --dport 21 -j ACCEPT # FTP service

iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT

Enable passive mode with a port range of 10001‑11000:

pasv_enable=YES

pasv_min_port=10001

pasv_max_port=11000

Allow the passive ports through the firewall:

iptables -A INPUT -p tcp --dport 10001::11000 -j ACCEPT # ftp passive ports

Configure virtual users

1. Create a password file /etc/vsftpd/vusers where odd lines are usernames and even lines are passwords, e.g.:

ftptest1

111111

ftptest2

222222

2. Generate the authentication database:

db_load -T -t hash -f /etc/vsftpd/vusers /etc/vsftpd/login.db

Set its permissions: chmod 600 login.db 3. Edit the PAM file /etc/pam.d/vsftpd to use the database:

auth    required    /lib64/security/pam_userdb.so  db=/etc/vsftpd/login

account required    /lib64/security/pam_userdb.so  db=/etc/vsftpd/login

4. Create a system user to own the virtual users’ directories (optional): # useradd -d /home/vsftp -s /sbin/nologin ftpuser Set directory permissions: # chmod 755 /home/vsftp/ 5. Add the following lines to /etc/vsftpd/vsftpd.conf to enable virtual users:

# Enable virtual user login

guest_enable=YES

# Map virtual users to a local user

guest_username=ftpuser

# PAM service name

pam_service_name=vsftpd

# Allow writable chroot

allow_writeable_chroot=YES

6. To give each virtual user a separate configuration file, add: user_config_dir=/etc/vsftpd/config Then create per‑user config files, for example for ftptest1:

local_root=/home/vsftp/ftptest1

download_enable=yes

anon_upload_enable=yes

anon_other_write_enable=YES

anon_mkdir_write_enable=yes

anon_world_readable_only=no

anon_max_rate=100000

Users without a dedicated config (e.g., ftptest2) will use the main configuration file.