How to Only permit specific users FTP Login
I have some hackers trying to get in through FTP login. They normally use users who do not exist. The FTP usernames we have are unique and would be very difficult to even guess the username let alone the corresponding password.
Anyway - I see people trying to get in via FTP with 'root' , 'postres', 'mysql' , etc.
I have used IPTables to block all SSH connections except from my IP or the console. That seems to be working wonders. What I would like to do is not the same though. I would like to block out all FTP connections except from the two usernames which I have in mind. How can I achieve this?