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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>That’s pretty sweet. Do you
know what fraction of firewalls “in the wild” allow for this
capability?<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>I’m no firewall nor security expert,
but I was under the impression a typical corporate firewall blocks most TCP
ports, and virtually (or even) all UDP ports. Do you have any stats on what
fraction of firewall users are able to take advantage of this feature?<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>-david<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> p2p-hackers-bounces@zgp.org
[mailto:p2p-hackers-bounces@zgp.org] <b><span style='font-weight:bold'>On
Behalf Of </span></b>Greg Bildson<br>
<b><span style='font-weight:bold'>Sent:</span></b> Tuesday, November 30, 2004
5:00 PM<br>
<b><span style='font-weight:bold'>To:</span></b> Peer-to-peer development.<br>
<b><span style='font-weight:bold'>Subject:</span></b> RE: [p2p-hackers] Why UDP
and not TCP?</span></font><o:p></o:p></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><font size=2 color=blue face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:blue'>David,</span></font><o:p></o:p></p>
</div>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
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<div>
<p class=MsoNormal><font size=2 color=blue face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:blue'>Yeah, the code has been in beta for a
while. </span></font><o:p></o:p></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=2 color=blue face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:blue'>It is UDP based. If all UDP is
blocked then it won't work and wont be attempted. We do a lot to first
ensure that you can receive solicited UDP which is what this feature relies
on. i.e. If you send a packet to X via UDP and you are behind a
NAT/Firewall, you can receive a response back. In LimeWire terms, you are
then said to be firewall capable and your searches and responses indicate
this. </span></font><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=blue face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:blue'> </span></font><o:p></o:p></p>
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<div>
<p class=MsoNormal><font size=2 color=blue face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:blue'>There are many ways to negotiate the
initiation of the connection on both sides. LimeWire has a concept of a
push proxy for firewalled hosts so we actually use that to deliver a special
PUSH message that tells the host to initiate a UDP connection to ip:port.
Both ends then start sending UDP messages at each other and shortly thereafter,
they should both be able to receive those messages. A type of TCP style
connection negotiation begins from there. Just to be clear, this is not
proxying. The only thing that is proxied, is the PUSH message to trigger
the actions of the uploader.</span></font><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
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<div>
<p class=MsoNormal><font size=2 color=blue face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:blue'>The FAQ is out of date.</span></font><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=2 color=blue face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:blue'>Thanks</span></font><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=blue face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:blue'>-greg</span></font><o:p></o:p></p>
</div>
<blockquote style='border:none;border-left:solid blue 1.5pt;padding:0in 0in 0in 4.0pt;
margin-left:3.75pt;margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt'>
<p class=MsoNormal style='margin-bottom:12.0pt'><font size=2 face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma'>-----Original Message-----<br>
<b><span style='font-weight:bold'>From:</span></b> p2p-hackers-bounces@zgp.org
[mailto:p2p-hackers-bounces@zgp.org]<b><span style='font-weight:bold'>On Behalf
Of </span></b>David Barrett<br>
<b><span style='font-weight:bold'>Sent:</span></b> Tuesday, November 30, 2004
6:28 PM<br>
<b><span style='font-weight:bold'>To:</span></b> 'Peer-to-peer development.'<br>
<b><span style='font-weight:bold'>Subject:</span></b> RE: [p2p-hackers] Why UDP
and not TCP?</span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>How does the Firewall-to-Firewall portion
of Limewire work? Does it use un-firewalled clients as relay
servers? It doesn’t sound like it, but I thought that’s the
only solution that truly works in all situations.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>The “features history” page
mentions this on the entry for 8.12.2004:<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=2 color=navy face=Arial><span
style='font-size:10.0pt;font-family:Arial;color:navy'>“Firewall to
Firewall transfers allows two people behind firewalls to connect directly to
each other and transfer data. <b><span style='font-weight:bold'>This makes use
of UDP, and a third party to coordinate the initial messaging.</span></b>
… Normally, firewalled users would only be able to download from other
hosts who are not firewalled, which is of course severely limited. With
firewall to firewall transfers, firewalled users can now access the full 100%
of hosts.”<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>This implies something like the NAT-to-NAT
trick works with firewalls also. I’m a little shaky on how UDP
works with firewalls, do both clients initiate a conversation with a third
party, and then the third party hands back information IP/port information of
the pre-established out-bound connection? How does this work if the
firewall simply blocks all UDP traffic?<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>However, the website is either out of date
or there’s more to the story because the FAQ says:<o:p></o:p></span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=2 color=navy face=Arial><span
style='font-size:10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=2 color=navy face=Arial><span
style='font-size:10.0pt;font-family:Arial;color:navy'><a
href="http://www.limewire.com/english/content/faq.shtml#fir1">http://www.limewire.com/english/content/faq.shtml#fir1</a>
<o:p></o:p></span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=2 color=navy face=Arial><span
style='font-size:10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=2 color=navy face=Arial><span
style='font-size:10.0pt;font-family:Arial;color:navy'>“Q: What if
I’m behind a firewall?<o:p></o:p></span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=2 color=navy face=Arial><span
style='font-size:10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=2 color=navy face=Arial><span
style='font-size:10.0pt;font-family:Arial;color:navy'>A: LimeWire will work
when a user is behind certain types of firewalls, but will not work behind
certain other types. <b><span style='font-weight:bold'>If you are behind a
firewall, you will not be able to download anything from a user that’s
also behind a firewall.</span></b> In general, if you can connect (you will see
your “connection status” in the lower left hand corner of the
application) using LimeWire, you should be able to download and upload files,
but LimeWire will not work if you have either a web-only proxy or a SOCKS
proxy.”<o:p></o:p></span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=2 color=navy face=Arial><span
style='font-size:10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>What’s the full story?<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>-david<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<div style='border:none;border-left:solid blue 1.5pt;padding:0in 0in 0in 4.0pt'>
<div>
<div class=MsoNormal align=center style='text-align:center'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>
<hr size=2 width="100%" align=center tabIndex=-1>
</span></font></div>
<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> p2p-hackers-bounces@zgp.org
[mailto:p2p-hackers-bounces@zgp.org] <b><span style='font-weight:bold'>On
Behalf Of </span></b>Greg Bildson<br>
<b><span style='font-weight:bold'>Sent:</span></b> Tuesday, November 30, 2004
2:12 PM<br>
<b><span style='font-weight:bold'>To:</span></b> Peer-to-peer development.<br>
<b><span style='font-weight:bold'>Subject:</span></b> RE: [p2p-hackers] Why UDP
and not TCP?</span></font><o:p></o:p></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:black'>If you believe that there are problems
with LimeWire, you should submit them to <a href="mailto:bugs@limewire">bugs@limewire</a> and
they will be looked into promptly. If you have not already, you
should also upgrade to version 4.2.3 to get rid of some potential startup issues
with old GWebcaches.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:black'> <o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:black'>LimeWire is a "good new" p2p
application - check out that firewall-to-firewall transfer in the new
version. ;)<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:black'> <o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:black'>Thanks<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:black'>-greg<o:p></o:p></span></font></p>
</div>
<blockquote style='border:none;border-left:solid black 1.5pt;padding:0in 0in 0in 4.0pt;
margin-left:3.75pt;margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt'>
<p class=MsoNormal style='margin-bottom:12.0pt'><font size=2 color=black
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma;color:black'>-----Original
Message-----<br>
<b><span style='font-weight:bold'>From:</span></b> p2p-hackers-bounces@zgp.org
[mailto:p2p-hackers-bounces@zgp.org]<b><span style='font-weight:bold'>On Behalf
Of </span></b>Digitalgruvmoves@aol.com<br>
<b><span style='font-weight:bold'>Sent:</span></b> Monday, November 29, 2004
9:10 PM<br>
<b><span style='font-weight:bold'>To:</span></b> p2p-hackers@zgp.org<br>
<b><span style='font-weight:bold'>Subject:</span></b> Re: [p2p-hackers] Why UDP
and not TCP?</span></font><font size=2 color=black face=Arial><span
style='font-size:10.0pt;font-family:Arial;color:black'><o:p></o:p></span></font></p>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial id="role_document"><span
style='font-size:10.0pt;font-family:Arial;color:black'>Whats a good new p2p
filesharing download to use? Limeware just started acting nuts.<o:p></o:p></span></font></p>
</div>
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