If you are using Samba over WAN I am actually horrified and a touch curious what lead you to that instead of a proper solution to file transfer. Samba is less secure than other solutions and actually harder to setup. Stopping the use of other utilities is both pointless and detrimental.
If you are running Samba over WAN, at least tunnel it through SSH or wrap it in a VPN.
If you are running Samba over WAN, at least tunnel it through SSH or wrap it in a VPN.