|The chief engineer at Rogers Cable Inc. says 1 per cent of the company's high-speed Internet customers are responsible for 30 per cent of the traffic on its network, a situation that has prompted a recent crackdown on abusers of the service.But Dermot O'Carroll expressed regret this week for sending out e-mails in February that threatened to disconnect thousands of legitimate users."Our wording of that e-mail left something to be desired," he said. "It sounded like we were going after everybody aggressively."Rogers sent the e-mails to anybody suspected of running servers on their computers. Servers allow computers on a network to be accessed and shared by other computers. Rogers can identify them by scanning its network for unprotected computer ports, which link network data to a particular server application.In the e-mail, Rogers cited section 7(k) of its user agreement, which forbids the use of servers. The e-mail then requested the server be removed, threatened disconnection, then warned that the "account will be checked in the future."O'Carroll said section 7(k) is only there so the company can take action against clear abusers. At the same time, he revealed Rogers is grappling with a serious problem that is taking a toll on the performance of its network."What we've discovered is there are a huge amount of servers out there, in the tens of thousands," he said. "A lot of people don't even know they're running one and don't realize they're very exposed to hackers and other attacks because they've got open ports."O'Carroll said "unfriendly people" can take advantage of these open ports by unleashing viruses. A personal firewall can prevent this from happening.Many subscribers are also using their servers to allow others to upload huge music, video and image files — often pornography, said O'Carroll, adding that other "legitimate" users can experience slower service as a result."We were spending huge amounts of money adding more capacity to the network, but in some cases that didn't do any good, because these people would use up all the bandwidth we were giving them," said O'Carroll. "What you have to do is target the abuse."Mark Quigley, research director at Yankee Group Canada, said the "cool stuff" that Rogers promotes in its advertising is at times what it disallows in practice. On the one hand, Rogers promotes its service as fast, reliable and capable of handling heavy-duty applications; on the other, it has to set limits on some for the benefit of all users. "Perhaps that is one argument for introducing some kind of usage cap, or charging people incremental fees for exceeding a traffic limit each month," said Quigley.