Security issue with USB data link (crossover) cables inquiry

[Shelly F]

I am going to purchase crossover cables to connect a pc and a laptop
together to transfer and synch some files, periodically.. Both use XP
SP2.
Both computers access the internet daily, one wirelessly but both
mostly high speed broadband thru a router and a cable modem with
ethernet adapters.
It is my understanding that the crossover cables such as Planet USB
Data Link cables (UL-PT201)installed with software which turns on file
sharing.
Doesn't this present a security issue - when I am not using the
crossover cables, file sharing is still on, and therefore can be
accessed from the internet by users unknown,,,,,,,is this correct?

 

[Yves Leclerc]

Just install a firewall and activate it only on the Ethernet adapters. You
should be able to tell a good software firewall (like Zone Alarm Free) which
network connections should be "protected".

But since you already have a router and Ethernet adapters, then your USB
transfer cable is "extra". You should really consider setting up a peer to
peer home network, since you have everything needed.

Router is connecting/controlling the cable modem. It should already have
some NAT firewall support.
The two PCs should already be assigned "private" IP addresses (ie: Class C:
192.168.xxx.yyy) where xxx, and yyy, are between 1 and 254. Private IP
addresses can not be "directly" seen on the Internet.