Xtra will crack down on users who are using file sharing software over JetStart connections.
Xtra's terms and conditions prohibit users from running servers over their connection and spokesman Matt Bostwick says users who are doing just that are responsible for a slow down in JetStart's service.
"Xtra JetStart has only ever been sold as a residential product and it's never been sold as something that could be used for those kinds of applications."
Bostwick says downloading files is fine, however uploading large amounts of traffic is causing the problems that some JetStart users are reporting.
The JetStart specific terms and conditions page on XtraMSN specifically rule out running servers over a JetStart connection.
"You must not run servers, use static IP addresses or provide public information service via a computer connected via this plan."
File sharing applications, such as KaZaA and Morpheus, have taken up the mantle left behind by Napster's closure. They allow users to share files, such as music or video files, between themselves. However, allowing someone to upload a file from a machine running on JetStart breaches the terms and conditions of the service.
"We do go to some effort to make sure these terms and conditions are understood by people before they sign up for a service."
Bostwick says Xtra will be looking at its options if customers continue to breach the terms and conditions.
"Obviously they do govern the use of the product and that's what we'll be referring to if indeed that is an issue."
Bostwick says the clause only applies to JetStart customers and not to JetStream users.
Last month Computerworld reported the case of a man whose children had been using Morpheus to download music files but hadn't realised the service also allowed other users to copy files from their machine. The bill came to $10,000 for three months' usage. Telecom reached a confidential settlement with the customer which is believed to have been at least $7000, possibly more.