[Shtoom] Fwd: [p2p-hackers] Final version of "P2P over NAT" paper available

Zooko O'Whielacronx zooko at zooko.com
Mon Feb 21 14:05:02 CET 2005


 From the p2p-hackers mailing list, discussion of the effectiveness of 
"hole-punching", e.g. sending a useless UDP packet to your peer, even 
though you know that your peer's NAT will discard it, in order to prime 
*your* NAT to accept incoming UDP packets from your peer.  See this new 
paper by Bryan Ford et al.:


Peer-to-Peer Communication Across Network Address Translators, Bryan 
Ford,
Pyda Srisuresh, and Dan Kegel. USENIX Annual Technical Conference, 
April 2005.
(PDF) http://www.brynosaurus.com/pub/net/p2pnat.pdf
(HTML) http://www.brynosaurus.com/pub/net/p2pnat/

--Z

Begin forwarded message:

> From: Alex Pankratov <ap at hamachi.cc>
> Date: 2005, February 19,  16:13:24 AST
> To: "Peer-to-peer development." <p2p-hackers at zgp.org>
> Subject: Re: [p2p-hackers] Final version of "P2P over NAT" paper 
> available
>
> Well, based on same stats it looks like 'hole punching' as it's
> described in p2pnat paper succeeds in ~84% of the cases. Our
> proggy is a bit more complex than that so our success rate is
> about 97%.
>
> Alex
>
> David Barrett wrote:
>
>> Heh, great validation of the results.
>> So if what's the latest values for the following chart:
>>                         NAT'd     Firewalled
>>                      +---------+-------------
>> % Able to hole punch |  82.2%  |   50-60% *
>> % of total internet  |   ??    |     ??
>>                      +---------+-------------
>> % Benefiting         |   ??    |     ??
>> * http://zgp.org/pipermail/p2p-hackers/2004-December/002215.html
>> Basically, I'd like to get a better understanding of what fraction of 
>> all
>> internet users might benefit from these techniques, estimated as the 
>> product
>> of the above rows.
>> -david
>>> -----Original Message-----
>>> From: p2p-hackers-bounces at zgp.org 
>>> [mailto:p2p-hackers-bounces at zgp.org] On
>>> Behalf Of Alex Pankratov
>>> Sent: Friday, February 18, 2005 11:04 PM
>>> To: Peer-to-peer development.
>>> Subject: Re: [p2p-hackers] Final version of "P2P over NAT" paper 
>>> available
>>>
>>> Bryan,
>>>
>>> Quoting your paper -
>>>
>>> > .. we find that about 82% of the NATs tested support hole punching
>>> > for UDP.
>>> > ..
>>>
>>>> The NAT Check data we gathered consists of 380 reported data points
>>>
>>> > ..
>>>
>>> I happened to have statistics for more than 16000 'data poits', and
>>> check this out - the rate of 'identity preserving' NAT devices 
>>> suitable
>>> for hole punching works out to be 82.2%. *UDP* hole punching that is.
>>>
>>> Alex
>>>
>>> Bryan Ford wrote:
>>>
>>>
>>>> Hi folks,
>>>>
>>>> For those interested in P2P-over-NAT issues, I just wanted to 
>>>> announce
>>>
>>> that
>>>
>>>> the final version of the following paper, to appear in USENIX '05, 
>>>> is
>>>
>>> now
>>>
>>>> available:
>>>>
>>>> Peer-to-Peer Communication Across Network Address Translators, Bryan
>>>
>>> Ford,
>>>
>>>> Pyda Srisuresh, and Dan Kegel. USENIX Annual Technical Conference, 
>>>> April
>>>> 2005.
>>>> (PDF) http://www.brynosaurus.com/pub/net/p2pnat.pdf
>>>> (HTML) http://www.brynosaurus.com/pub/net/p2pnat/
>>>>
>>>> An earlier draft of this paper was announced on this list a few 
>>>> months
>>>
>>> ago.
>>>
>>>> The final version includes, among other minor revisions, new "NAT 
>>>> Check"
>>>> testing results based on almost twice the number of data points as 
>>>> the
>>>> original draft.
>>>>
>>>> Cheers,
>>>> Bryan
>>>>
>>>> ---
>>>>
>>>> Abstract:
>>>>
>>>> Network Address Translation (NAT) causes well-known difficulties for
>>>> peer-to-peer (P2P) communication, since the peers involved may not 
>>>> be
>>>> reachable at any globally valid IP address. Several NAT traversal
>>>
>>> techniques
>>>
>>>> are known, but their documentation is slim, and data about their
>>>
>>> robustness
>>>
>>>> or relative merits is slimmer. This paper documents and analyzes 
>>>> one of
>>>
>>> the
>>>
>>>> simplest but most robust and practical NAT traversal techniques,
>>>
>>> commonly
>>>
>>>> known as ``hole punching.'' Hole punching is moderately 
>>>> well-understood
>>>
>>> for
>>>
>>>> UDP communication, but we show how it can be reliably used to set up
>>>> peer-to-peer TCP streams as well. After gathering data on the
>>>
>>> reliability of
>>>
>>>> this technique on a wide variety of deployed NATs, we find that 
>>>> about
>>>
>>> 82% of
>>>
>>>> the NATs tested support hole punching for UDP, and about 64% support
>>>
>>> hole
>>>
>>>> punching for TCP streams. As NAT vendors become increasingly 
>>>> conscious
>>>
>>> of the
>>>
>>>> needs of important P2P applications such as Voice over IP and online
>>>
>>> gaming
>>>
>>>> protocols, support for hole punching is likely to increase in the
>>>
>>> future.
>>>
>>>> _______________________________________________
>>>> p2p-hackers mailing list
>>>> p2p-hackers at zgp.org
>>>> http://zgp.org/mailman/listinfo/p2p-hackers
>>>> _______________________________________________
>>>> Here is a web page listing P2P Conferences:
>>>> http://www.neurogrid.net/twiki/bin/view/Main/PeerToPeerConferences
>>>>
>>>>
>>>
>>> _______________________________________________
>>> p2p-hackers mailing list
>>> p2p-hackers at zgp.org
>>> http://zgp.org/mailman/listinfo/p2p-hackers
>>> _______________________________________________
>>> Here is a web page listing P2P Conferences:
>>> http://www.neurogrid.net/twiki/bin/view/Main/PeerToPeerConferences
>> _______________________________________________
>> p2p-hackers mailing list
>> p2p-hackers at zgp.org
>> http://zgp.org/mailman/listinfo/p2p-hackers
>> _______________________________________________
>> Here is a web page listing P2P Conferences:
>> http://www.neurogrid.net/twiki/bin/view/Main/PeerToPeerConferences
> _______________________________________________
> p2p-hackers mailing list
> p2p-hackers at zgp.org
> http://zgp.org/mailman/listinfo/p2p-hackers
> _______________________________________________
> Here is a web page listing P2P Conferences:
> http://www.neurogrid.net/twiki/bin/view/Main/PeerToPeerConferences
>




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