From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Ray Subject: Re: filtering .mp3 packets Date: Fri, 29 Apr 2005 08:43:42 -0300 Message-ID: <42721DEE.7020102@mrmighty.net> References: <001a01c54b7c$6da1b7f0$660aa8c0@descartes2> <427030A8.8020604@comarre.com> <4b0d6e0d050428200525186e50@mail.gmail.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4b0d6e0d050428200525186e50@mail.gmail.com> Sender: linux-newbie-owner@vger.kernel.org List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: joy_mm@ieee.org Cc: linux-newbie@vger.kernel.org I don't know about compression, but I see two problems with filtering based on mp3 headers (other than the apparent lack of tools supporting it). The first is that some p2p protocols, such as Bittorrent, divide the files into chunks, sending and receiving them out of order. So the header may be the last part of the file to be sent. The other problem is that in any protocol, an mp3 file is going to be too big for a tcp/ip packet. It seems very likely that an mp3 packet will be split across two or more packets. That would make identification more problematic, as you would have to make sure that a header fragment was a header fragment, and not part of a legitimate file that happens to be coincidentally identical to part of a mp3 header. Stephen joy merwin monteiro wrote: > Hi, > > Since this thread dealt mainly with blocking p2p downloading of > mp3s since they consume large b/w, and has come to a discussion of > https and scp, > I wanted to know wether any p2p protocol uses the above...... > or even wehter they use compression....... > > if neither is the case, what John said seems to be reasonable,, since > MP3 _has_ to have a header...... > > blocking all outgoing http requests for or blocking all incoming MP3's > will prevent genuine users who need it. alternatively, there should be > a limit of connections that a user can open at a single time to get > MP3s... since most p2p protocol that i've encountered always try to process > the waiting list as fast as possible by downloading multiple files all > at once.... > > Comments. anyone? > > regards, > Joy > > - To unsubscribe from this list: send the line "unsubscribe linux-newbie" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.linux-learn.org/faqs