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Bitcoin => Bitcoin Technical Support => Topic started by: jnano on August 18, 2019, 01:01:42 PM



Title: Testnet block time in the future?!
Post by: jnano on August 18, 2019, 01:01:42 PM
I thought blocks don't store a timestamp, but the time of testnet block 1,575,038 appears to be 19 minutes in the future:
https://blockstream.info/testnet/block/000000008ec4318ee2e3dc84424a68252ed0b4552bb2ff8a309fbf28f6fb3a85
https://testnet.smartbit.com.au/block/000000008ec4318ee2e3dc84424a68252ed0b4552bb2ff8a309fbf28f6fb3a85

Also Core shows it similarly.

What's going on here?


Title: Re: Block time in the future?!
Post by: Rath_ on August 18, 2019, 01:12:08 PM
Attacks on Bitcoin testnet happen quite often due to small amount of miners interested in mining worthless testnet coins. Also, there is...

A piece of code which is intended to allow a difficulty 1 block is none has been found in 20 minutes also enables a person to "warp" forward and mine multiple in a row. If this is exploited over the difficulty adjustment, the entire chain difficulty is reset to difficulty 1


Title: Re: Testnet block time in the future?!
Post by: achow101 on August 18, 2019, 03:48:01 PM
Blocks have a timestamp. Since not all computer clocks will be synchronized to exactly the same time (if that were the case, then the blockchain would not be needed), the timestamp reported by a block's header can be ahead of or behind the previous block's timestamp. There is some leeway to the timestamp.


Title: Re: Testnet block time in the future?!
Post by: jnano on August 18, 2019, 04:59:18 PM
20 minutes into the future is rather major. What's the use of the timestamp if it can't be relied upon?

I briefly searched the mainnet. A few recent blocks with bad times correlate with empty blocks for some reason: 542,094 (https://www.smartbit.com.au/block/542094), 566,083 (https://www.smartbit.com.au/block/566083), 567,902 (https://www.smartbit.com.au/block/567902).

In the old days there was an early block that's 1 hour late: 6,844 (https://www.smartbit.com.au/block/6844).




Title: Re: Testnet block time in the future?!
Post by: ETFbitcoin on August 18, 2019, 05:07:47 PM
20 minutes into the future is rather major. What's the use of the timestamp if it can't be relied upon?

I understand what you meant, but we're talking about P2P network where such accuracy can't be guaranteed and doesn't mean it can't be relied at all.

On a side note, according to https://en.bitcoin.it/wiki/Block_timestamp (https://en.bitcoin.it/wiki/Block_timestamp), block time which accepted are

A timestamp is accepted as valid if it is greater than the median timestamp of previous 11 blocks, and less than the network-adjusted time + 2 hours. "Network-adjusted time" is the median of the timestamps returned by all nodes connected to you. As a result block timestamps are not exactly accurate, and they do not need to be. Block times are accurate only to within an hour or two.


Title: Re: Testnet block time in the future?!
Post by: undeadbitcoiner on August 18, 2019, 05:09:02 PM
By the way anyone has Idea where i can mine Testnet? As i know Ckpool is no more mining testnet. Any information regarding this will be helpful.
I have a project where i am needing 10 ti 17 Btc so was thinking about mining with my miners which i am using to mine bitcoin but didn't see any working pool.
Please if you have knowledge on that or anywhere i can get 10 to 17 tBTC i would love to hear that.


Title: Re: Testnet block time in the future?!
Post by: jnano on August 18, 2019, 05:11:47 PM
Maybe you can mine by yourself?
Perhaps there's a chance when the difficulty resets, after no block was found for 20 mins.


Title: Re: Testnet block time in the future?!
Post by: ETFbitcoin on August 18, 2019, 05:16:42 PM
By the way anyone has Idea where i can mine Testnet? As i know Ckpool is no more mining testnet. Any information regarding this will be helpful.
I have a project where i am needing 10 ti 17 Btc so was thinking about mining with my miners which i am using to mine bitcoin but didn't see any working pool.
Please if you have knowledge on that or anywhere i can get 10 to 17 tBTC i would love to hear that.

If your project doesn't involve mining, you could contact this user (studio_mining (https://bitcointalk.org/index.php?action=profile;u=1925846)) for some tBTC.

There are few tBTC faucet website, but most of them either ran out of coins or no longer maintained.


Title: Re: Testnet block time in the future?!
Post by: undeadbitcoiner on August 18, 2019, 05:25:44 PM
By the way anyone has Idea where i can mine Testnet? As i know Ckpool is no more mining testnet. Any information regarding this will be helpful.
I have a project where i am needing 10 ti 17 Btc so was thinking about mining with my miners which i am using to mine bitcoin but didn't see any working pool.
Please if you have knowledge on that or anywhere i can get 10 to 17 tBTC i would love to hear that.

If your project doesn't involve mining, you could contact this user (studio_mining (https://bitcointalk.org/index.php?action=profile;u=1925846)) for some tBTC.

There are few tBTC faucet website, but most of them either ran out of coins or no longer maintained.
Thank you for the info.
No my project doesn't require mining (It does in some projects but I can use that while mining Bitcoin)
Was in need of tBTC so i was thinking if there is no other way i can use my miners for sometime so i can get atleast 17 tBRC for the project and be back to Bitcoin mining.
I will contact if i can get some.