Several people wrote to correct my inexact terminology in talking about URLs pointing at files available on the nets via FTP (and, at times in the future, Gopher or the World-Wide Web). URLs are not part of the HyperText Markup Language (HTML) as such, although they are somewhat related, given their joint usage on the World-Wide Web.
Smarter Parental Controls
If you've been using the parental controls options in Mac OS X to lock your child out of using a particular computer late at night, but would like to employ a more clever technique to limit Internet access, turn to MAC address filtering on an Apple base station.
To do this, launch AirPort Utility, select your base station, and click Manual Setup. In the Access Control view, choose Time Access to turn on MAC filtering. You'll need to enter the MAC address of the particular computer, which (in 10.5 Leopard and 10.6 Snow Leopard) you can find in the Network System Preferences pane: click AirPort in the adapter list, and click Advanced. The AirPort ID is the MAC address.