Did you happen to see this in the Parallels Help?
"Select Host-only networking if you don't want your virtual machine to be accessible from outside your Macintosh computer, or if the network interfaces of your Mac are off. Withe [sic] this option chose [sic], your virtual machine will be connected to the host computer and other virtual machines, but it will be disconnected from the Internet. [emphasis added]"
Last edited: May 12, 2008