On Sun, Nov 04, 2007 at 10:42:26AM -0500, Bob Goodwin wrote:
Should I open this port? would it benefit the Windows and Mac users on my LAN?
Only if you want to share services that use it (iTunes or rhythmbox music share, some other stuff).
If so will it do that without increasing traffic to and from my ISP?
mDNS and bonjour/rendevouz work only in your LAN, they don't go to/from the internet. (non-routable local multicast address)