Harvard has not yet decided how to respond to a written request from an attorney representing rapper Dr. Dre and rock group Metallica urging university officials to prevent students from accessing the music sharing program Napster.

University Attorney Allan A. Ryan Jr. confirmed Friday that the General Counsel's office had received the letter, sent to University President Neil L. Rudenstine.

The letter requests a reply by September 22.

Unlike similar efforts last spring to restrict student access to Napster at Yale and other schools, the letter to Rudenstine makes no explicit threat of legal action.

Instead, it posits that Harvard "has a moral, ethical and legal obligation" to prevent copyright infringement over its networks.

"I believe that you can easily recognize the irony of encouraging your students to matriculate in the creative arts, while engaging in behavior which, if unchecked, will make it impossible for those students to earn an income from their future creative efforts," wrote Howard E. King, the attorney.

Ryan told the Crimson last spring that he did not think the University would ban Napster traffic.

"I don't think there's an obligation to prevent our users from accessing protected material over the Internet," Ryan said.

Last spring, King filed suit against several universities that allowed students to access Napster through their dorm computers.

Several of the universities, including Yale, responded by banning the site.

Letters similar to the one sent to Harvard were also sent to Boston University, the Georgia Institute of Technology, the Massachusetts Institute of Technology, Princeton University, the University of Michigan at Ann Arbor, the University of California at Berkeley and the University of California at Los Angeles.

While King and other lawyers for recording artists have focused most of their legal efforts on blocking Napster, other programs that allow users to trade music are waiting in the wings, and may prove far more difficult to shut down.

Programs like Gnutella allow file-sharing without a central server that houses information about who its users are, making it very difficult to block access to the program.

The battle over Napster has divided musicians and industry officials.

There are those who say the music industry must adapt to a wired world. They point to the decades long rise in CD prices, even as manufacturing costs came down and to data that shows Napster may actually increase sales of CDs by music-hungry customers, as evidence that the music industry is simply afraid of a new technology.

In the other camp are those who argue that Napster is nothing more than a tool for the wholesale infringement of intellectual property rights. Artists like Metallica and Dr. Dre argue that users will not be willing to purchase music if they can get it for free on the Internet, and artists will therefore not be properly rewarded for their effort.