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From: Matt Whitlock <bip@mattwhitlock•name>
To: Jim Phillips <jim@ergophobia•org>
Cc: Bitcoin Dev <bitcoin-development@lists•sourceforge.net>
Subject: Re: [Bitcoin-development] Zero-Conf for Full Node Discovery
Date: Tue, 26 May 2015 00:52:07 -0400	[thread overview]
Message-ID: <23111107.dfGN69SrR9@crushinator> (raw)
In-Reply-To: <CANe1mWzeLsOWv+2qwx1b3s61HqCwy5GLd2Rv3LgWLrOa_jkFjw@mail.gmail.com>

On Monday, 25 May 2015, at 11:48 pm, Jim Phillips wrote:
> Do any wallets actually do this yet?

Not that I know of, but they do seed their address database via DNS, which you can poison if you control the LAN's DNS resolver. I did this for a Bitcoin-only Wi-Fi network I operated at a remote festival. We had well over a hundred lightweight wallets, all trying to connect to the Bitcoin P2P network over a very bandwidth-constrained Internet link, so I poisoned the DNS and rejected all outbound connection attempts on port 8333, to force all the wallets to connect to a single local full node, which had connectivity to a single remote node over the Internet. Thus, all the lightweight wallets at the festival had Bitcoin network connectivity, but we only needed to backhaul the Bitcoin network's transaction traffic once.



> On May 25, 2015 11:37 PM, "Matt Whitlock" <bip@mattwhitlock•name> wrote:
> 
> > This is very simple to do. Just ping the "all nodes" address (ff02::1) and
> > try connecting to TCP port 8333 of each node that responds. Shouldn't take
> > but more than a few milliseconds on any but the most densely populated LANs.
> >
> >
> > On Monday, 25 May 2015, at 11:06 pm, Jim Phillips wrote:
> > > Is there any work being done on using some kind of zero-conf service
> > > discovery protocol so that lightweight clients can find a full node on
> > the
> > > same LAN to peer with rather than having to tie up WAN bandwidth?
> > >
> > > I envision a future where lightweight devices within a home use SPV over
> > > WiFi to connect with a home server which in turn relays the transactions
> > > they create out to the larger and faster relays on the Internet.
> > >
> > > In a situation where there are hundreds or thousands of small SPV devices
> > > in a single home (if 21, Inc. is successful) monitoring the blockchain,
> > > this could result in lower traffic across the slow WAN connection.  And
> > > yes, I realize it could potentially take a LOT of these devices before
> > the
> > > total bandwidth is greater than downloading a full copy of the
> > blockchain,
> > > but there's other reasons to host your own full node -- trust being one.
> > >
> > > --
> > > *James G. Phillips IV*
> > > <https://plus.google.com/u/0/113107039501292625391/posts>
> > > <http://www.linkedin.com/in/ergophobe>
> > >
> > > *"Don't bunt. Aim out of the ball park. Aim for the company of
> > immortals."
> > > -- David Ogilvy*
> > >
> > >  *This message was created with 100% recycled electrons. Please think
> > twice
> > > before printing.*
> >



  reply	other threads:[~2015-05-26  4:52 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-05-26  4:06 Jim Phillips
2015-05-26  4:37 ` Matt Whitlock
2015-05-26  4:46   ` Kevin Greene
2015-05-26  4:56     ` Matt Whitlock
2015-05-26  5:12       ` Kevin Greene
2015-05-26  5:23     ` Luke Dashjr
2015-05-26  4:48   ` Jim Phillips
2015-05-26  4:52     ` Matt Whitlock [this message]
2015-05-26  5:15       ` Peter Todd
2015-05-26  5:47         ` Matt Whitlock
2015-05-26 10:48           ` Mike Hearn
2015-05-27 10:16             ` Louis Rossouw

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