FTP

Install a FTP server on Linux and start service:

yum -y install vsftpd
systemctl start vsftpd
firewall-cmd --zone=public --add-port=21/tcp [--permanent]

Add a user for FTP:

useradd <username> -s /sbin/nologin # can't log in system
password <username>

Customize relative configurations in /etc/vsftpd/vsftpd.conf like:

anonymous_enable=NO

userlist_enable=YES
userlist_deny=NO
userlist_file=/etc/vsftpd/user_list

Then edit /etc/vsftpd/user_list, commenting other users and adding created above to specify the only user whose can access to FTP. Remember restarting the server.

Notes: Users in the file ftpusers are always forbidden for security. If userlist_enable=NO, all users except those in ftpusers are allowed to access to the server. If userlist_enable=YES, who can access to the server depends on the file specified by userlist_file. It's a blacklist when userlist_deny=YES, otherwise, it's a whitelist.

Access to the server (here is from Command Line):

ftp <ip>
User(ip:(none)): anonymous # it will fail if anonymous_enable is set NO.
password: # no password
Login successful.
ftp >