More than two dozen vendors say they can help ISPs filter unwanted P2P traffic. But only two were willing to put marketing claims on the line in an in-depth test of P2P filtering technology.

You might not have a problem with sharing copyrighted music and video files over the Internet, but two groups clearly do: entertainment conglomerates and ISPs. Entertainment companies, particularly record labels, have watched profits fall in direct correlation with the adoption of file-sharing technology. Suing people, including the dead , for sharing files hasn't staunched the bleeding.

Meanwhile, ISPs that sell flat-rate broadband access view bandwidth-hogging P2P apps with the same horror that farmers do locust plagues.

Smelling a market opportunity, at least two dozen vendors claim to have the capability to identify and regulate P2P traffic on the Internet.

But a new report, posted on Internet Evolution, raises serious questions about these claims.

Internet Evolution and SNEP (Syndicat National de l'Edition), a French music industry organization, commissioned an independent test of P2P filtering products. The testing company invited 28 vendors, including major players such as Cisco and Juniper, to participate.

A mere five stepped up to the plate, and only under the condition that they could withdraw the results from the report if they didn't like them, sort of like a "get out of jail free" card.

Of the five that underwent testing, only two companies -- Ellacoya (recently acquired by Arbor Networks) and Ipoque -- allowed their results to be published.

As you can guess, Ellacoya and Ipoque did fairly well. Though not able to achieve perfect results in identifying and controlling P2P applications, both proved robust enough to be well worth a look.

Lab tests always have limitations because they are, by definition, an artificial environment. That said, the test bed seemed well-designed and thorough. I’d encourage you to check out the full report on Internet Evolution. And if you're in the market for a P2P filter, you've got a decent shortlist right in front of you.