<p>To double check, the genesis block for testnet3 (the current version as of this writing) has hash <code>000000000933ea01ad0ee984209779baaec3ced90fa3f408719526f8d77f4943</code>.  So with the daemon running, you can do</p>

<pre> bitcoind -testnet getblock 000000000933ea01ad0ee984209779baaec3ced90fa3f408719526f8d77f4943</pre>

<p>If you are really on testnet3, you should see "height: 0" in the output.</p>

CC BY-SA 3.0
2013-11-06T17:03:33.537Z
2013-11-06T17:03:33.537Z
Nate Eldredge
<ul>
<li>Bitcoin and bitcoind versions v0.3.14 - v0.3.19 used the first testnet.</li>
<li>Bitcoin, Bitcoin-Qt and bitcoind versions v0.3.20 - v0.6.1 used the second testnet.</li>
<li>Bitcoin-Qt and bitcoind version v0.7.0 and above use the third testnet.</li>
</ul>

CC BY-SA 3.0
2013-06-15T20:37:09.367Z
Oh, so it's hardcoded in the client, I didn't know that.
o0'.
CC BY-SA 3.0
2013-06-16T09:05:02.670Z
The different testnets have slightly different rules, and a separate genesis block, so yes, they are hardcoded. No point in trying to support multiple versions.
Pieter Wuille
CC BY-SA 3.0
2013-06-15T20:11:05.197Z
2013-06-15T20:11:05.197Z
Pieter Wuille
<p>How can I know which testnet am I on?</p>

<p>I just ran <code>bitcoind -testnet</code>, and I would assume it would connect to the most recent one, but is there a way to <em>know</em> it?</p>

<bitcoind><testnet>
Which testnet am I on?
o0'.
# Which testnet am I on?

(Asked by: username_0 on 2013-06-15)

How can I know which testnet am I on?

I just ran `bitcoind -testnet`, and I would assume it would connect to the most recent one, but is there a way to *know* it?

**Tags:** bitcoind, testnet


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## 2 answers

### Answer by username_2 on 2013-06-15. Score: 4 | Accepted answer

* Bitcoin and bitcoind versions v0.3.14 - v0.3.19 used the first testnet.
* Bitcoin, Bitcoin-Qt and bitcoind versions v0.3.20 - v0.6.1 used the second testnet.
* Bitcoin-Qt and bitcoind version v0.7.0 and above use the third testnet.

> **Comments:**
> **username_0**: Oh, so it's hardcoded in the client, I didn't know that.  
> **username_2**: The different testnets have slightly different rules, and a separate genesis block, so yes, they are hardcoded. No point in trying to support multiple versions.  

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### Answer by username_1 on 2013-11-06. Score: 1

To double check, the genesis block for testnet3 (the current version as of this writing) has hash 000000000933ea01ad0ee984209779baaec3ced90fa3f408719526f8d77f4943.  So with the daemon running, you can do
 bitcoind -testnet getblock 000000000933ea01ad0ee984209779baaec3ced90fa3f408719526f8d77f4943
If you are really on testnet3, you should see "height: 0" in the output.


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