<p>You can run Bitcoin with the -connect=192.168.1.3 (or whatever) switch to connect one local node to another one.</p>

<p>This will still not get the blocks <em>super</em> quickly, since the second node still needs to build a database and verify every transaction in the chain.</p>

CC BY-SA 3.0
2011-10-19T19:45:02.547Z
A typical PC will only be able to verify about 40 blocks per second, regardless of how fast it can receive them. So a typical PC will need more than an hour to go from zero blocks to fully synched.
David Schwartz
CC BY-SA 3.0
2012-04-13T15:06:47.050Z
Note that not "every transaction in the chain" is verified, only transactions after the most recent checkpoint.  See a post I made about this here: https://bitcointalk.org/index.php?topic=74275.msg823763#msg823763
Chris Moore
CC BY-SA 3.0
2011-10-19T06:19:21.093Z
2011-10-19T06:19:21.093Z
theymos
<p>This is the scenario:</p>

<ul>
<li>2 computers on a LAN with private IPs (192.168.X.X)</li>
<li>router forwards port 8333 only to one of them (the 2nd one).</li>
<li>one computer has the full blockchain updated in its Bitcoin client, </li>
<li>the 2nd computer has only half the size of the block chain (Bitcoin client has not been run for a long time).</li>
</ul>

<p>Why doesn't the Bitcoin client from the second computer detect the first computer and receive the remaining missing blocks at high LAN speed?</p>

<p>What i see is a very slow update of the chain on the 2nd computer.</p>

CC BY-SA 3.0
2011-10-19T19:45:56.337Z
How slow is 'very slow'? About how many blocks per second?
David Schwartz
<client><blockchain>
Why isn't there a fast blockchain update inside a LAN behind a router between two Bitcoin clients?
thedrs
# Why isn't there a fast blockchain update inside a LAN behind a router between two Bitcoin clients?

(Asked by: username_0 on 2011-10-19)

This is the scenario:

* 2 computers on a LAN with private IPs (192.168.X.X)
* router forwards port 8333 only to one of them (the 2nd one).
* one computer has the full blockchain updated in its Bitcoin client,
* the 2nd computer has only half the size of the block chain (Bitcoin client has not been run for a long time).

Why doesn't the Bitcoin client from the second computer detect the first computer and receive the remaining missing blocks at high LAN speed?

What i see is a very slow update of the chain on the 2nd computer.

**Tags:** client, blockchain

> **Comments:**
> **username_1**: How slow is 'very slow'? About how many blocks per second?  

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## 1 answers

### Answer by username_2 on 2011-10-19. Score: 9

You can run Bitcoin with the -connect=192.168.1.3 (or whatever) switch to connect one local node to another one.

This will still not get the blocks *super* quickly, since the second node still needs to build a database and verify every transaction in the chain.

> **Comments:**
> **username_1**: A typical PC will only be able to verify about 40 blocks per second, regardless of how fast it can receive them. So a typical PC will need more than an hour to go from zero blocks to fully synched.  
> **username_3**: Note that not "every transaction in the chain" is verified, only transactions after the most recent checkpoint.  See a post I made about this here: https://bitcointalk.org/index.php?topic=74275.msg823763#msg823763  

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