Enabling anonymous-only download appears to be enabled by default, so I am not sure why this is an objective. Below are the steps needed in case it isnt in the future.
- Install packages – yum install vsftpd ftp
- Edit /etc/vsftpd/vsftpd.conf
- Find the line anonymous_enabled and set it to YES
- Ensure anon_upload_enabled is set to NO
- Restart ftp – service vsftpd restart