The /etc/ftphosts file is used to define whether users are allowed to log in from certain hosts or whether there are denied access.
Create the ftphosts file, touch /etc/ftphosts and add for example in this file the following lines:
# Example host access file
#
# Everything after a '#' is treated as comment,
# empty lines are ignored
allow ftpadmin 208.164.186.1 208.164.186.2 208.164.186.4
deny ftpadmin 208.164.186.5
In the example below, we allow the user ftpadmin to connect via FTP from the explicitly listed addresses 208.164.186.1 208.164.186.2 208.164.186.4, and
deny the specified ftpadmin user to connect from the site 208.164.186.5.
Now, change its default permission to be 600:
[root@deep ] /# chmod 600 /etc/ftphosts
The /etc/ftpusers/ file specifies those users that are NOT allowed to connect to your FTP server.
Create the ftpusers file, touch /etc/ftpusers and add in this file the following users for security reasons:
root
bin
daemon
adm
lp
sync
shutdown
halt
mail
news
uucp
operator
games
nobody
Now, change its default permission to be 600:
[root@deep ] /# chmod 600 /etc/ftpusers