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Title: Getting block headers
Post by: jackjack on April 20, 2013, 09:55:35 AM

Hi
I ran into something strange when I'm downloading block hashes from bitcoin nodes (let's call my script 'BD')
When I'm connecting to 63.247.147.163 (all fallback nodes on the wiki* behave the same way), the following happens:

BD sends version
BD receives version and verack
BD sends verack
BD regularly receives tx inv's (about 1 per second)

Moreover, sending getblocks doesn't change anything and I still receive only tx inv's

On the other hand, when I connect to my local bitcoin node (127.0.0.1 ofc), that becomes:

BD sends version
BD receives version and verack
BD sends verack
BD receives tons of block hash inv's (yeah, TONS OF THEM)

I didn't even try to send a getblocks...

So, why does my local node behaves differently than the other ones?

(*) all the nodes I tested on http://blockchain.info/connected-nodes too

Edit: 98.26.149.98:8333 sends me some block headers after a getblocks

Title: Re: Getting block headers
Post by: Zeilap on April 20, 2013, 10:52:49 AM

Is your local node syncing at the time?

There is a new field in the version message you send which tells the other peer not to send you inv's like this.

To receive block headers, you need to ask with a 'getheaders' message, it doesn't follow the 'getblocks' -> receive 'inv' -> 'getdata' -> receive block message sequence.

Title: Re: Getting block headers
Post by: jackjack on April 20, 2013, 10:57:24 AM

Absolutely
Does this change anything? I didn't saw anything about it
I didn't finish reading https://en.bitcoin.it/wiki/Satoshi_Client_Block_Exchange though

Edit:
I just checked what the two responding nodes (localhost and 98.26...) and it looks like they are sending me their last blocks
localhost is sending me hashes of blocks number ~134k

Title: Re: Getting block headers
Post by: Zeilap on April 20, 2013, 11:27:43 AM

The client will relay invs to its other peers for every new block it receives. If it's syncing, then it receives a lot of new blocks and so you get a lot of invs.

Title: Re: Getting block headers
Post by: jackjack on April 20, 2013, 11:34:53 AM

Thanks!

I didn't see your edit

Quote from: Zeilap on April 20, 2013, 10:52:49 AM

There is a new field in the version message you send which tells the other peer not to send you inv's like this.

Thanks a lot, that'll clean my display

Quote from: Zeilap on April 20, 2013, 10:52:49 AM

To receive block headers, you need to ask with a 'getheaders' message, it doesn't follow the 'getblocks' -> receive 'inv' -> 'getdata' -> receive block message sequence.

Yeah, I was mixing getheaders and getblocks

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Bitcoin => Development & Technical Discussion => Topic started by: jackjack on April 20, 2013, 09:55:35 AM