We call on crossing guards and police officers to help keep our kids safe on the streets, but our main line of defense is the family.

Kids are taught to look both ways when they cross the street and to wear seat belts when riding in cars. Very young children are not even allowed on the street unless we're holding their hand. Most of the time things work out for the best because we follow the basic rules of the road.

The same is true when it comes to Internet safety. Congress can pass all the laws it wants and civil-liberties groups can challenge those laws, but regardless of what the government does, it's up to parents and kids themselves to assure a safe passage while online.

Over the past several years, I've written hundreds of pages on this subject but it doesn't take a user's manual -- or a federal law -- to figure out how to protect our kids online. It's mostly a matter of common sense and knowing a few simple rules.

The first thing to understand is the difference between what is safe and what is appropriate. There are lots of places on the Internet that are inappropriate for kids. Porn sites, for example, can be disturbing or possibly even psychologically damaging, but -- with a few exceptions -- they do not jeopardize a child's physical safety. Of course, we should do what we can to keep kids away from these sites, but we should also develop priorities. Job one is keeping them away from predators who would do them harm. Job two is helping keep their online experiences comfortable and nourishing. Both jobs are important, but the first is critical.

Helping to regulate what kids do online is a bit like dealing with what they eat. There is no ``one-size-fits-all'' answer. I know some parents who wouldn't dream of allowing their kids to consume sugar or food that isn't organically grown. Others have no qualms about letting their kids snack on soda pop, candy bars and potato chips. Some parents, mostly outside of the United States, even allow their children small amounts of alcohol. If we can't all agree on something as basic as what kids ought to be allowed to put in their stomachs, how can all agree as to what should go into their minds?

We do, of course, all agree that kids should be protected from predators. There are two cardinal rules that all children and teenagers should follow: Never give out information online that can help a predator find you in the real world. Your child's real name, address, phone number and even e-mail address should be kept confidential. And kids should never get together with someone they meet online without checking with their parents. If parents agree to such a meeting, it should be in a public place with the parents present. The teen version of this rule varies only slightly. You should never go alone to a face-to-face meeting with someone you only know from the Internet.

It's also important that kids not give out their Internet password, that they tell their parents about anything that makes them feel uncomfortable and that they not respond to messages that are mean or threatening. If these rules sound familiar, it's because they're adapted from ``My Rules for Online Safety'' which has been circulating in print and on the Internet ever since I wrote ``Child Safety on the Information Highway'' for the National Center for Missing and Exploited Children back in 1994. You can read the entire booklet at www.safekids.com.

But even if your kids are physically safe, it doesn't mean they are being well-nourished by the Internet. Most of us want our kids to stay away from Web sites that display pornography or advocate violence, hatred or the use of tobacco, alcohol and recreational drugs. We also want them to avoid sites that are fraudulent, overly pushy or just plain stupid.

How we keep our kids safe and well-nourished varies, depending on the child's age and individual characteristics as well as our parenting styles and our family's values. Some safety tips based on a child's age are in ``The Online Safety Guide'' I wrote for GetNetWise.org, an industry-sponsored child-safety site.

Very young children shouldn't be online unless accompanied by a parent. As they get older, they should be given more freedom, but they should never be completely on their own.

Parents of pre-teens or young teens should consider using a filter or an Internet provider like MSN or AOL that offers parental controls, but you still need to monitor your kids. These controls don't necessarily protect kids from everything that can be harmful and they sometimes block Web sites and activities that you may want to allow. Study them carefully before you implement them.

Teenagers may be as big as adults, but they're not as mature. Teens -- especially girls -- are actually more vulnerable than young children to sexual assault and other serious dangers. Teens get ``hit on'' regularly in chat rooms, and because they are more independent than small children they are more likely to get into dangerous situations both online and off. The guidelines at www.safeteens.com don't exactly make for fun teenage reading, but they can help keep them from harm's way.

My advice to parents is to take a deep breath, relax and spend as much time with your kids as you can. My parents' generation survived the Jitterbug, the Depression and World War II. Mine survived the sexual revolution, recreational drugs and Vietnam. Trust me; your kids will survive the Internet.