Not to be too blunt here but opening your miners to the internet like that is the single dumbest thing you could ever do.

This is because the firmware on those devices, the versions of the programs it runs, etc are all well known and do not change with 'firmware updates'

So its really easy to find an exploit for anything it is running as they do not and cannot update.

You need to have a VPN of some sort protecting you if you want to access them on the internet.

This can be done with a raspberry pi very cheaply

Here is the software I would recommend for a beginner doing this: http://www.pivpn.io/