p2p, anonymity and security

[greg at freephile.com (Greg Rundlett)]

I have several goals in the area of peer-to-peer technologies (or 
distributed client-server, whatever you want to call it.)  I figured 
this would be a great topic of discussion, and although I certainly have 
more questions than answers at this point, I'd bet it would make a great 
topic at an upcoming LUG meeting.

I would like to get bittorrent working, to be able to download ISO's and 
free software more quickly than perhaps I've been able to in the past, 
and at the same time donate my spare bandwidth to those around me who 
are looking for the same files.

I also want to get a general purpose p2p tool similar to Napster, for 
sharing ogg, mp3 or other multimedia files.  The number one prerequisite 
here is which tool/protocol offers the best anonymity.

Last, but not least, I am finally taking steps to secure my little 
lan-behind-a-linksys.  I have not had the time to understand iptable 
incantations, but it looks to me that a good script for setting up 
access to these various networks is found at the link below.  It 
includes a succinct rundown of the various ports to open in your 
firewall, with descriptions of the networks:

http://mldonkey.berlios.de/modules.php?name=Wiki&pagename=WhatFirewallPortsToOpen

I downloaded KMLDonkey, plus MLDonkey and am pleasantly surprised that 
MLDonkey can support various networks, including bittorrent.  The web 
client interface for mldonkey is quite impressive, so you really don't 
need KMLDonkey.  (Note that MLDonkey would not install without doing the 
local install of objectCAML and LablGTK)

I poked a few holes in my Linksys to forward packets to my Linux server.

So, my first question...Is a Linksys Router doing 'firewall' duty and 
NAT easy to get past?  If the answer is yes, then what should I do?  Use 
a firewall-specific distro to convert my old P133MHz box into a Linux 
firewall?  Maybe someone wants $100 to come over and show me how it's 
done? (location Newburyport, MA or E. Kingston, NH)

Secondly, for true anonymity, I'm guessing you would have to add a layer 
somewhere along the lines, because even in a decentralized system, you 
still have a source PC 'A' (potentially) logging transactions and 
destination IPs, which then can be correlated to a netblock, to an ISP 
'B', to a customer 'C'.  So if PC 'A' is confiscated, or monitored, and 
ISP 'B' is served with a John Doe suit, then wham-o 'C' is out $2,500 to 
the RIAA because teenagers like to download music.  Anyone using this 
anonymizer layer?

Lastly, I can't tell yet if I still need to go through the setup of my 
.torrent files and download them etc. as described in the BitTorrent 
site (http://bitconjurer.org/BitTorrent/guide.html).  If anyone knows 
whether mldonkey will do this automagically for me, I'd like to know.

Thanks,

Greg