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What's All the Fuss?

So, you ask, why are persistent DSL and cable modem connections riskier than traditional modem access? Part of the trouble is that unlike dial-up modems, broadband solutions typically rely on "static," or fixed, IP addresses. (Your IP address is a number that identifies your PC when it connects to the Internet.) With a dial-up modem, every time you call in to connect, your Internet service provider assigns you an IP address. Under that scheme, even if hackers find your computer once, they might never find it again because your IP address is different each time you dial in.

But because DSL and cable modem connections are always on, they're usually assigned static IPs, so every time you surf the Web, your PC has the same IP address it had before. Some providers, including US West and Southwestern Bell, now offer DSL service with dynamic IP addressing, which allocates a different IP address each time you boot the PC. While that fix doesn't make persistent connections 100 percent secure, it does help--assuming you don't keep your PC on all the time. If you're signing up for DSL, ask whether dynamic addressing is available. If it is--and especially if it doesn't cost extra--get it.