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When a new node joins the network, it will look up nodes from the DNS seeds. It'll reach out to multiple nodes it hears about and ask them for more peers in turn. The new node asks each of their peers for their best chaintip and then starts sychronizing the headers of the best chaintip it hears about first. A block header is only 80 bytes (tiny in comparison ...


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Each non-pruning full node (peer) stores a complete copy of the blockchain - pruned nodes store a complete copy of the current state, but may not have all historical blocks available. When a node validates a transaction or a block, it is only validating it against its local view of the blockchain - this means that looking up data is pretty fast, since all ...


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So can a blockchain can be shutdown by shutting down power supply across the globe? What would happen in such a case? If the world's power supply was suddenly cut off, then everything electronic would stop working. The blockchain would be 'frozen', each node would retain its local copy, but be unable to communicate with other nodes, and miners would be ...


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Bitcoin is a gossip network and relays transaction or blocks on a best effort basis. Hence you cannot determine the probability of one transaction being seen by the network versus the other. Now in terms of mining the transactions in a block there are a couple of cases that needs to be considered. For assumption sake let us assume that we are considering a ...


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Your node will just ask its peers for blocks. It actually does the same thing it does for the initial sync. It starts with what it currently considers to be the chain tip (in initial sync, that's the genesis block). From there, it connects to other nodes and asks those nodes for more block headers starting with the block at its own chain tip. Typically, that ...


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But what if all the eight nodes to whom a given node send the transaction are malicious/faulty? And all of them change the message in the original transaction. Wouldn't it allow for wrong transaction to get merged in the blockchain network? Transactions have signatures that sign the whole transaction (except signatures. Signatures are added after the ...


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To put it simply, blockchain is essentially a history of transactions, with built in measures to confirm that this transaction history cannot be altered. That being said, transactions can be either spent or unspent. Spent transactions are transactions that have already been used as inputs in another transaction. Unspent transactions are transactions that ...


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Yes a full node downloads and verifies all blocks starting from the genesis block. Not on every startup though, the state is efficiently stored and read back into memory on startup (with some rechecking of the last X blocks as a sanity check against corruption). For finding the right chain, it starts with downloading the headers first, with which it can ...


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Nodes that participate in the Bitcoin network run a computer program such as this one: https://github.com/bitcoin/bitcoin, which dictates how everything works. To answer your more specific questions: Yes, bitcoin once used UPnP, here are some more details: https://dirkmittler.homeip.net/blog/archives/3340 but in modern versions it does not (thanks for ...


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