Thread: Router Tricks

MANY APARENT, exasperated by children goofing off on the Internet when they
should be doing their homework, has searched for a techno¬logical solution. The technology certainly exists: Programs such as Net Nanny and Safe Eyes are mature and have remote admin¬istration so parents don't have to be present to manage things. Windows Vista actually comes with parental controls that let you filter content and application types and control usage by time of day. These programs al¬so send usage reports to the parent. But content filtering and access control tend to exist as software utilities, installed, configured, and run on the specific PCs they control.

A network device, perhaps an appliance, might be a better way to go, as it could provide network-wide control. And, in fact, there are dozens of net¬work appliances for access control and content filtering-it's just that they're geared toward businesses. But home users probably do have a broad¬band router from a company like Link¬sys, D-Link, or Netgear. Scan through your router's manual or the tabs in the administration program and you might be surprised by the inclusion of access control, and possibly even content-fil- tering features.

I scouted around manuals from the major companies' mainstream home models and found a certain baseline of features. These are only barely, if at all, helpful to novice users. The first confus¬ing aspect of home-router controls is that most of them rely on the IP addresses of your PCs. This means you have to specify the addresses of the kids' computers, even though you almost certainly set them up as DHCP (Dynamic Host Configuration Protocol) clients, meaning you won't necessarily know their addresses. Some routers let you specify the MAC (media access control) address instead, and this is technically better, because every net¬work adapter in each PC has a unique, persistent MAC address-although you'll still have to figure out which MAC address goes with which computer.



So, What Can You Do?
Almost all routers have a basic time¬of-day control, through which you can specify that a PC with a specific IP or MAC address can connect only during particular hours. Better ones let you specify which applications can be used when-but to a router, the term "applications" probably refers to TCP ports. For example, you can block AOL Instant Messaging by blocking TCP ports 5190 to 5193. The official list of port assign¬ments is at/assign¬ments/port-numbers, but I warn you, it's ugly. I far prefer Wikipedia's format (en.wikipedia.org/wiki/Lisc oLTCP _and_ UDP _porcnumbers).

Finally, some routers actually let you filter content, though primitively. You can specify a URL blacklist. This just isn't worth the work, especially if you can't combine it with time-of-day control; for example, you might want to block Disney. com while your children should be doing homework, but probably not at all times.

The potential for more sophisticated parental-control options at the network level is emerging, but as best as I can tell, there is nothing great in the way of new products right now. Parents who need a solution should buy PC software. For our reviews and other articles about Web filtering and other parental-control software.