Don't be caught napping

ITworld.com –

What is Napster? According to the company Website, Napster is "a completely new way of thinking about music online." That's for sure.

Napster automates the process of searching for and downloading MP3-format digitized music files. What used to be a long, frustrating process that involved searching for shady FTP sites that were usually overloaded with downloaders is now a snap, thanks to Napster.

Napster offers a registration server that the client on a user's PC contacts when it starts the application. The client registers with the server and uploads an index of all the music files currently available on the user's machine.

Napster thus turns machines on which it is installed into servers. All their MP3 files are available to anyone else that's using Napster. As I write this there's more than 910 GB of music being offered by 1,720 clients.

Given that the biggest users of Napster are students and that many educational institutions now provide a switched 10 Mbps port to each dorm resident, it's easy to see how bandwidth consumption can skyrocket.

Just how much of a load does Napster put on the network? Over a five-day period, Napster traffic originating on Duke University's residential network network consumed an average of 20 to 30 megabits per second. On numerous occasions the Napster traffic made up more than 50 percent of Duke's total outbound bandwidth utilization. More than 250 GB of Napster data was was transferred during the past weekend.

Is there a way to curtail Napster? Technically, yes. Napster uses TCP port 6699 as default. Putting a filter in the residential network and Internet routers that block this port brings Napster traffic to a screeching halt. halt. We've tried it and it works. Blocking www.napster.com adds an extra measure of security, as all clients must contact the site before they can begin begin exchanging music files.

But simply forbidding the use of Napster and blocking access to the site isn't the best approach. Crafty programmers would quickly come up with a way around the port blocking -- Napster already allows users to choose their own port -- and mirrored servers with new names would get around the site block.

An alternative for network managers is to assign a priority level to Napster traffic. Your routers can be configured to allocate only so much bandwidth to Napster traffic, dropping packets when bandwidth consumption exceeds the threshold. This approach puts a heavier load on the routers but has the advantage of not explicitly blocking the traffic.

There will be more services like Napster popping up in the future. So what can be done? Education. Launch an information blitz describing copyright violation and the penalties for it. Show users how their PCs are being turned into servers. Give folks a chance to do the right thing and most of them will.

Meanwhile, begin thinking about assigning quality of service capabilities to your network.

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