Don't be caught napping

By Robert Currier, |  Software

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 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

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.

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