Net Daemons Associates, in Woburn, Mass., provides computer-network and system administration support as well as Internet services. When its managers realized that someone had hacked into the company's computer system, founders Christopher Caldwell and Jennifer Lawton went into red-alert mode. Not only had the company's data been compromised, but so had data belonging to some of its biggest clients.

Lawton and Caldwell personally called the clients whose sites had been hit and gingerly broke the news. Their reactions surprised Lawton. "No one freaked out," she recalls. "Some were even relieved that the break-in happened." The attack alerted them to gaps in their security so that they were able to ward off future hits. In essence, the attack had served as a security check.

You don't have to wait for a similar attack to find the holes in your system's security. Hire a consultant, intern, or a techno-savvy friend to try to hack into your system and discover its weaknesses. You should discover problems sooner rather than later, and it's better to get the news from someone you trust.