public inbox for bitcoindev@googlegroups.com
 help / color / mirror / Atom feed
From: Matt Corallo <lf-lists@mattcorallo.com>
To: Juan Garavaglia <jg@112bit.com>,
	Bitcoin Protocol Discussion
	<bitcoin-dev@lists.linuxfoundation.org>,
	Juan Garavaglia via bitcoin-dev
	<bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Issolated Bitcoin Nodes
Date: Thu, 23 Mar 2017 23:01:09 +0000	[thread overview]
Message-ID: <9752F0E1-A339-4A2D-9574-843DE32AE5A3@mattcorallo.com> (raw)
In-Reply-To: <SC1P152MB1648D0F9DF4279C49D755233F53F0@SC1P152MB1648.LAMP152.PROD.OUTLOOK.COM>

[-- Attachment #1: Type: text/plain, Size: 2462 bytes --]

I haven't investigated, but you may be seeing segwit-invalid blocks...0.13.0+ nodes will enforce segwit as it activated some time ago on testnet, 0.12.X nodes will not.

On March 23, 2017 3:37:34 PM PDT, Juan Garavaglia via bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org> wrote:
>We notice some reorgs in Bitcoin testnet, while reorgs in testnet are
>common and may be part of different tests and experiments, it seems the
>forks are not created by a single user and multiple blocks were mined
>by different users in each chain.  My first impression was that the
>problem was related to network issues but some Bitcoin explorers were
>following one chain while others follow the other one.  Nonetheless,
>well established explorers like blocktrail.com or blockr.io were
>following different chains at different heights which led to me to
>believe that it was not a network issue. After some time, a reorg
>occurs and it all comes to normal state as a single chain.
>We started investigating more and we identified that the fork occurs
>with nodes 0.12; in some situations, nodes 0.12 has longer/different
>chains. The blocks in both chains are valid so something must be
>occurring in the communication between nodes but not related with the
>network itself.
>Long story short, when nodes 0.13+ receive blocks from 0.13+ nodes all
>is ok, and those blocks propagate to older nodes with no issues. But
>when a block tries to be propagated from bitcoind 0.12.+ to newer ones
>those blocks are NOT being propagated to the peers with newer versions
>while these newer blocks are being propagated to peers with older
>versions with no issues.
>My conclusion is that we have a backward compatibility issue between
>0.13.X+ and older versions.
>The issue is simple to replicate, first, get latest version of
>bitcoind, complete the IBD after is at current height, then force it to
>use exclusively one or more peers of versions 0.12.X and older, and you
>will notice that the latest version node will never receive a new
>block.
>Probably some alternative bitcoin implementations act as bridges
>between these two versions and facilitate the chain reorgs.
>I have not yet found any way where/how it can be used in a malicious
>way or be exploited by a miner but in theory Bitcoin 0.13.X+ should
>remain compatible with older ones, but a 0.13+ node may become isolated
>by 0.12 peers, and there is not notice for the node owner.

[-- Attachment #2: Type: text/html, Size: 4662 bytes --]

  reply	other threads:[~2017-03-23 23:28 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-23 22:37 [bitcoin-dev] Issolated Bitcoin Nodes Juan Garavaglia
2017-03-23 23:01 ` Matt Corallo [this message]
2017-03-23 23:14 ` Andrew Chow
2017-03-24  3:38   ` Andrew Chow
2017-03-24  0:20 ` Pieter Wuille
2017-03-24  0:31   ` James Hilliard
2017-03-24  1:58   ` Eric Voskuil

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=9752F0E1-A339-4A2D-9574-843DE32AE5A3@mattcorallo.com \
    --to=lf-lists@mattcorallo.com \
    --cc=bitcoin-dev@lists.linuxfoundation.org \
    --cc=jg@112bit.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox