To: Eric Voskuil <eric@voskuil.org>,
	Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
References: <e2fd3226-91ff-d0ca-67c7-2c4a98c6628f@voskuil.org>
	<620d4b5e-61c4-4501-9787-c73109908418@achow101.com>
	<8C660724-A76D-44C1-9140-AD3215768CE1@voskuil.org>
From: Andrew Chow <achow101-lists@achow101.com>
Message-ID: <1659f63f-5003-40d5-85a9-11e7a8f34edb@achow101.com>
Date: Thu, 15 Mar 2018 11:44:43 -0400
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Subject: Re: [bitcoin-dev] version.relay behavior change
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I don't think the nodes that you are connecting to that have this
behavior are actually forked from Bitcoin Core. It seems more like fake
nodes - nodes that don't actually do any verification or follow the
protocol. Such fake nodes can set whatever user agent they want, common
ones being Bitcoin Core's user agents.

IMO your best solution would be to drop peers for protocol noncompliance.

Andrew


On 03/15/2018 05:17 AM, Eric Voskuil wrote:
> Thanks for the reply Andrew. I’ve reviewed the relevant Core sources
> and I do not see any problem. We have also synced against a Core node
> locally and not seen the problem.
>
> The reason I suspected it was Core is that it is very common and all
> of the User Agents are consistent (with an occasional exception for
> forked nodes). So there’s no easy way to determine what sort of nodes
> we are seeing. 
>
> We tend to cycle through many more connections during sync than a Core
> node, so may just be seeing it more frequently, but I assume Core
> would log this behavior as well. Even so, seeing that wouldn’t help
> much. I’m as certain as I can be at this point that we are setting the
> flag and version correctly (and that we do not set bip37 filters).
>
> This behavior started infrequently with 0.14.0 peers and has become
> more common over time. Just wondering at this point what fork would
> report as Core and be that common? We used to drop peers that did this
> (for protocol noncompliance), and I’m considering reinstating that
> behavior.
>
> e
>
> On Mar 9, 2018, at 16:33, Andrew Chow via bitcoin-dev
> <bitcoin-dev@lists.linuxfoundation.org
> <mailto:bitcoin-dev@lists.linuxfoundation.org>> wrote:
>
>> Looking through the code, I don't think that this behavior has
>> changed. Are you sure that you are actually connected to
>> Satoshi:0.15.0 nodes and not a node that has simply set their
>> user-agent to that (i.e. not a real Satoshi:0.15.0 node)?
>>
>> If what you are seeing is true, it is likely a bug and not an
>> intentional change. In that case, can you provide specific details on
>> how to reproduce?
>>
>> Andrew
>>
>>
>> On 03/09/2018 02:50 AM, Eric Voskuil via bitcoin-dev wrote:
>>> /Satoshi:0.15.0/ and later nodes appear to be no longer honoring the
>>> version.relay=false flag (BIP37). Could someone familiar with the change
>>> please explain the rational?
>>>
>>> Thanks,
>>>
>>> e
>>>
>>>
>>>
>>> _______________________________________________
>>> bitcoin-dev mailing list
>>> bitcoin-dev@lists.linuxfoundation.org
>>> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>>
>> _______________________________________________
>> bitcoin-dev mailing list
>> bitcoin-dev@lists.linuxfoundation.org
>> <mailto:bitcoin-dev@lists.linuxfoundation.org>
>> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev


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    <p>I don't think the nodes that you are connecting to that have this
      behavior are actually forked from Bitcoin Core. It seems more like
      fake nodes - nodes that don't actually do any verification or
      follow the protocol. Such fake nodes can set whatever user agent
      they want, common ones being Bitcoin Core's user agents.</p>
    <p>IMO your best solution would be to drop peers for protocol
      noncompliance.</p>
    <p>Andrew<br>
    </p>
    <br>
    <div class="moz-cite-prefix">On 03/15/2018 05:17 AM, Eric Voskuil
      wrote:<br>
    </div>
    <blockquote type="cite"
      cite="mid:8C660724-A76D-44C1-9140-AD3215768CE1@voskuil.org">
      <meta http-equiv="content-type" content="text/html; charset=utf-8">
      <div>Thanks for the reply Andrew. I’ve reviewed the relevant Core
        sources and I do not see any problem. We have also synced
        against a Core node locally and not seen the problem.</div>
      <div><br>
      </div>
      <div>The reason I suspected it was Core is that it is very common
        and all of the User Agents are consistent (with an occasional
        exception for forked nodes). So there’s no easy way to determine
        what sort of nodes we are seeing. </div>
      <div><br>
      </div>
      <div>We tend to cycle through many more connections during sync
        than a Core node, so may just be seeing it more frequently, but
        I assume Core would log this behavior as well. Even so, seeing
        that wouldn’t help much. I’m as certain as I can be at this
        point that we are setting the flag and version correctly (and
        that we do not set bip37 filters).</div>
      <div><br>
      </div>
      <div>This behavior started infrequently with 0.14.0 peers and has
        become more common over time. Just wondering at this point what
        fork would report as Core and be that common? We used to drop
        peers that did this (for protocol noncompliance), and I’m
        considering reinstating that behavior.</div>
      <div><br>
      </div>
      <div>e</div>
      <div><br>
        On Mar 9, 2018, at 16:33, Andrew Chow via bitcoin-dev &lt;<a
          href="mailto:bitcoin-dev@lists.linuxfoundation.org"
          moz-do-not-send="true">bitcoin-dev@lists.linuxfoundation.org</a>&gt;
        wrote:<br>
        <br>
      </div>
      <blockquote type="cite">
        <div>
          <meta http-equiv="Content-Type" content="text/html;
            charset=utf-8">
          <p>Looking through the code, I don't think that this behavior
            has changed. Are you sure that you are actually connected to
            Satoshi:0.15.0 nodes and not a node that has simply set
            their user-agent to that (i.e. not a real Satoshi:0.15.0
            node)?</p>
          <p>If what you are seeing is true, it is likely a bug and not
            an intentional change. In that case, can you provide
            specific details on how to reproduce?</p>
          <p>Andrew<br>
          </p>
          <br>
          <div class="moz-cite-prefix">On 03/09/2018 02:50 AM, Eric
            Voskuil via bitcoin-dev wrote:<br>
          </div>
          <blockquote type="cite"
            cite="mid:e2fd3226-91ff-d0ca-67c7-2c4a98c6628f@voskuil.org">
            <pre wrap="">/Satoshi:0.15.0/ and later nodes appear to be no longer honoring the
version.relay=false flag (BIP37). Could someone familiar with the change
please explain the rational?

Thanks,

e

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            <pre wrap="">_______________________________________________
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</pre>
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      <blockquote type="cite">
        <div><span>_______________________________________________</span><br>
          <span>bitcoin-dev mailing list</span><br>
          <span><a href="mailto:bitcoin-dev@lists.linuxfoundation.org"
              moz-do-not-send="true">bitcoin-dev@lists.linuxfoundation.org</a></span><br>
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              href="https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev"
              moz-do-not-send="true">https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev</a></span><br>
        </div>
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