When Washington College tripled the size of its Internet connection last year, officials at the Chestertown, Md., school thought they would have plenty of room on their network for students, faculty and staff.

They were wrong.

The extra Internet capacity was rapidly soaked up by students downloading music and movies through peer-to-peer (p2p) file-sharing programs. The result was that the school's Internet access was more clogged than ever, choked off by file-sharing networks that use all the space they can get.

"[File-sharing applications] would dominate the network from about two in the afternoon until two in the morning," said Billie S. Dodge, the school's director of information technologies, who said the school dealt with the problem by restricting the bandwidth available to students this year.

Like Washington College, many schools are limiting student access to the Internet and turning to costly fixes to deal with the unwanted interloper of peer-to-peer file-sharing networks.

These programs let students download files directly from other users' computers instead of detouring through a central server. But in the process, they siphon off bandwidth, introduce viruses and divert school resources.

At the University of Maryland, College Park, one freshman woman spent much of last semester downloading music for a Music History class -- along with about 2,500 songs for her own use.

"I'd do it while I was doing my homework, because I was already on the Internet for a class or something," said the student, who would not give her full name. "I got all the songs I could ever want."

While she was using the popular Kazaa program to get her music, other users around the world were downloading songs from her computer as well, eating away at the university's network.

"[Peer-to-peer file sharing] significantly slowed our Internet access for resident hall students," said Joan Martinez, a spokeswoman for the school.

The programs slowed the access so much that students themselves began complaining in the fall, Martinez said.

School officials also noticed viruses that were likely spread by the file-sharing networks, since those applications can bring in and spread files so quickly.

The "p2p" programs were taking such a bite out of the network that officials at College Park bought PacketShaper, a software/hardware package that restricts bandwidth to the residence halls. Martinez said it has helped, but at a price: $70,000 for the package, which is expected to last for only two to three years.

Mount St. Mary's College and Seminary in Emmitsburg, Md., also turned to PacketShaper when file-sharing applications threatened to overwhelm the college's network.

"The p2p applications all try to use as much bandwidth as available for each download," wrote Barbara Jarc, the college's network manager, in an e-mail. "So even three or four students using Kazaa, for instance, could potentially use up our entire pipe."

Now Jarc limits Internet traffic to make sure that the bandwidth is available when it is needed, primarily during the day.

Peer-to-peer file sharing took up so much bandwidth at Morgan State University that "it would slow down the whole campus" at times, said Joseph Popovich, a vice president there.

Even setting school routers so students could not connect to some services did not stop the problem, he said, since the students and the software both found ways around the restrictions.

Instead, the school segmented its network, separating residence hall traffic from other locations, Popovich said, bringing the network back to speed.

But he said the problem at Morgan State was also less severe than at other schools because relatively few students there own computers. Of the 2,000 students who live on campus, Popovich estimates that only "about 400 to 500 have their own computers in their rooms."

"The vast majority of our students use computers in our computer labs," where they are supervised and cannot save files to hard drives or CDs, he said.

At Washington College, the bandwidth restrictions on students have cleared more lanes on the information superhighway for other users, said Dodge.

While there are still some file-sharing problems, the network is now running more smoothly overall.

Even though her school has won the battle, the war continues.

"Next week, [programmers] could put out something new and we could have different problems," she said. "What saves us today might not save us tomorrow."