Securely sharing a folder on a wifi network

Question

I was successfully able to share an external hard drive between my mac and Windows machine over wifi by enabling file sharing in the Windows properties of the selected drive (see method HERE). What I have discovered is that by doing this I have created a security risk by opening the following ports: TCP 139, 445 UDP 137, 138 (see description of security issue HERE)

What I need to know now is this: How do I enable this file sharing securely so that there are not constant brute force attacks on this port?

Running Windows7 64 bit

Answer 1

Assuming this is your home network and you have the typical router/firewall combo that comes with the service, then you are safe. Those ports are open on the internal LAN, but not accessible through the internet. Those ports are blocked by default.