Bitcoin Stack Exchange
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Questions tagged [peers]

should be used for questions related to the peers of the bitcoin network

Any computer that connects to the Bitcoin network is called a node (peer). Nodes that fully verify all of the rules of Bitcoin are called full nodes. The most popular software implementation of full nodes is called Bitcoin Core

https://en.bitcoin.it/wiki/Full_node

126 questions
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Why doesn’t Bitcoin use UDP to do Blockpropagation?

Bitcoin uses TCP for P2P but why is UDP not used? Modern day internet has relatively low packet loss rate so UDP is reliable. Even if some packets are dropped the peers can always request for the blocks. With TCP, the network is rather staticly…
user2584960
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What is the difference between inbound and outbound connections?

I have port 8333 open with 8 outbound and 2 inbound connections. Is my node transmitting and receiving transactions and blocks from both types of connections? Or does the "inbound" flag mean I am just downloading from that peer, and not sending any…
pinhead
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How do I read peers.dat file to get a list of all peers seen or that bitcoind has connected to?

In version 0.8.6 of Bitcoin, I see that peers.dat file is a custom database format declared in db.h:317 (class CAddrDB) and defined in dh.cpp:485. Any ideas on how I could go about reading the data from peers.dat with PHP or Python? I'd like to keep…
Konstantin
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Can an unconfirmed transaction that only Blockchain.info shows be manually re-broadcast?

Blockchain.info shows a transaction that was created by Blockchain.info/wallet but for whatever reason the transaction didn't confirm right away and appears to not be getting re-broadcast (perhaps because the transaction is more than a day old…
Stephen Gornick
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What happens to transactions in the mempool when their parent transaction expires?

I was just reading the Coin Metrics Newsletter #53, and it included a section about the recent mempool congestion. After mentioning transactions that got evicted due to the network's queue of unconfirmed transactions exceeding the default mempool…
Murch
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5 answers

How blocks are created and broadcast?

Followings are some of my understandings about how bitcoin blockchain works, and want to confirm. Appreciate your comments and thoughts. In the blockchain, every peer receives both transactions and blocks. A peer will store the transactions they…
Qi Zhang
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What is the difference between blocksonly and block-relay-only in Bitcoin Core?

The terms blocksonly and block-relay-only that are used in Bitcoin Core are very similar. What is the difference between them?
Lightlike
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How do I still have connections without forwarding port 8333?

First of all, this isn't a problem I am having, I'm just curious how this works. If you run your node with port 8333 open, you'll receive a large amount of connections after being online for a while. If you run your node without port 8333, you…
m1xolyd1an
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How peer discovery works after connecting to hardcoded nodes?

I am tinkering with the bitcoin source code and trying to understand the exact working of peer discovery mechanism in the testnet mode for which I have made the following changes: Disabled the DNS seed discovery in order to force bitcoind to…
bawejakunal
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Looking for a better way of listing all my peers

I am looking for a cheap and efficient way (rather than hacking through the Bitcoin source code) of listing my peers. Something I have come up with: #!/bin/bash netstat -p tcp -nba | grep '.8333.*ESTABLISHED' | perl -npe…
Ning
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Could the BGP attack be used to split the Bitcoin network?

I just learnt about the BGP attack: http://www.wired.com/2014/08/isp-bitcoin-theft/ http://www.secureworks.com/cyber-threat-intelligence/threats/bgp-hijacking-for-cryptocurrency-profit/ The attacker was able to redirect the miners to its own pool to…
Manish
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What is a block-relay-only connection? What is it used for?

Modern versions of bitcoin core establish a fixed number of outbound connections: 8 outbound-full-relay connections and 2 block-relay-only connections. What is the purpose of block-relay-only connections and how are they used? Here are two example…
vnprc
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How to make bitcoind connect to more nodes?

Let's say I have a dedicated server just for my bitcoind and for better reliability and some security reasons I want it to be connected to a much bigger number of nodes than it is willing to do by default (about 40-50). Providing that I have enough…
knaperek
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What is a Feeler Connection? When is it used?

The bitcoin client hard codes a limit of 8 outbound connections and 2 block-only connections. Your node will try to always maintain these 10 outbound connections with reliable peers as a defense against network attacks. But there is an ephemeral…
vnprc
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Bitcoin Core stalled peer logic during initial block download

I'm trying to track down the cause of unexpected (20% to 85%) IBD slowdowns between my 2020 and 2021 annual performance tests. I experienced this slowdown with multiple implementations, so I don't think the issue is Bitcoin Core specific, though I…
Jameson Lopp
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