11 votes

What exactly does the scary option "Allow incoming connections" do in Bitcoin Core?

There are two ways by which bitcoind connects to peers. The default is purely outbound connections - the node will use DNS seeds, as well as its own database of previously seen peers, and attempt to ...
Raghav Sood's user avatar
9 votes
Accepted

Is there a connections limit on bitcoind?

By default, bitcoin-core allows up to 125 connections to different peers, 8 of which are outbound. You can therefore, have at most 117 inbound connections. I think there is no need to handhold ...
Jonas Schnelli's user avatar
9 votes

List transactions *relayed* by my full node?

Blockchain.info lists the first IP address it sees a new transaction from. If you aren't the one creating the transaction, and aren't accidentally the node right in between the node that does and ...
Pieter Wuille's user avatar
6 votes

Are nodes that don't accept inbound connections necessarily leechers?

An outbound connection is functionally equivalent to an inbound connection except in the respect that you initiated it. An outbound only node provides the same resources to the network except that it ...
G. Maxwell's user avatar
  • 7,727
6 votes

Allowing Incoming Connection on Bitcoin Core

I had the same problem. The port was open, but the test at bitnodes.21.co would fail. However after my Bitcoin client downloaded the entire BlockChain everything worked. I used about 144 hours to ...
Jack Brennan's user avatar
6 votes

With peerblockfilters=1 hundreds of "btcwire 0.5.0/neutrino" connections are downloading TB from my Bitcoin node

It appears that btcwire is the Bitcoin p2p module of btcd and neutrino is Lightning Labs's implementation of BIP157/158 (compact client-side block filters (CBF)). I suspect that the agent identifier ...
Murch's user avatar
  • 75.3k
5 votes
Accepted

Is 8 the maximum number of incoming peer connections?

The reference here for running the bitcoin daemon does not really clarify what maxconnections mean. Furthermore, that maxconnections only controls the number of inbound connections and not outbound. ...
Nick ODell's user avatar
  • 29.4k
5 votes

What's a rule of thumb for setting the maximum number of connections?

The -maxconnections setting primarily controls how many inbound connections a peer can accept. The number of outbound ones is independently limited (~10), so unless -maxconnections is set lower than ...
Pieter Wuille's user avatar
4 votes
Accepted

Bitcoin V0.1 Not Connected

You cannot. There have been both changes to the P2P protocol that prevent this, and changes to the way that nodes are discovered. The method which 0.1.0 discovered new nodes was by joining the #...
Ava Chow's user avatar
  • 70.4k
4 votes
Accepted

Does bitcoin-core software/client connects with only same version number nodes?

You can see from the Debug Window ("Peers" tab) that the Bitcoin Core client connects with multiple clients not only with different versions but different implementations. So to answer your question: ...
mishmash's user avatar
  • 152
3 votes

Sybil attack countermeasure

When you are buying servers you can order multiple IP per one server, typically in the same /8 or /16 subnet. So 1 server can serve as 100 or even 1000 Bitcoin nodes. Ordering lots of IPs in lots of ...
BarsMonster's user avatar
3 votes

How does blockchain ensure that a closed loop in network is not formed?

Nodes have more than 8 connection slots, by default they have 125 maximum connections. There are 8 outbound connections, but can still have incoming connections from other nodes when all 8 outbound ...
Ava Chow's user avatar
  • 70.4k
3 votes
Accepted

Does having a pruned node reduce its network score?

What's the meaning of the score in getnetworkinfo? When you look up getnetworkinfo in the Bitcoin Developer Reference, it says about score: The number of incoming connections during the uptime of ...
Murch's user avatar
  • 75.3k
2 votes

How does one node connect to other nodes

There is no centralised server required. 1. If you start a node the first time, it will try to load a bunch of other nodes IPs via the build in list of available DNS seeds (there are ~5 seeds ...
Jonas Schnelli's user avatar
2 votes

Warning: Reducing -maxconnections from 1000 to 865, because of system limitations

Connecting to more nodes will not make you learn about transactions faster, after some point. Your node will just be busy processing messages - including many uninteresting ones - to maintain ...
Pieter Wuille's user avatar
2 votes

What exactly does the scary option "Allow incoming connections" do in Bitcoin Core?

A network is formed by computers connecting to other computers. If nobody had that option turned on there would be no network, and no bitcoin. It's possible for some fraction of the nodes to ...
hobbs's user avatar
  • 121
2 votes
Accepted

Is a peer connection maintained for the life of the node, or is it recreated on every request?

Or is the connection persisted for the life time of the application? Persistent. Subsequent messages will be transmitted across the same connection. If it is persisted, what prevents a well known ...
rny's user avatar
  • 2,418
2 votes

How does the Bitcoin p2p network work? Does it need port forwarding?

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: ...
bitfede's user avatar
  • 54
2 votes
Accepted

Can I connect to a node as read-only?

It is important to note that your Electrum wallets connect to Electrum servers which speak a different protocol than the Bitcoin P2P network. Electrum servers are full nodes with additional software ...
Ava Chow's user avatar
  • 70.4k
2 votes

Only 10 connections on my raspberry pi full node

bind=127.0.0.1 Binding the p2p port to localhost means that it can not accept incoming connections from anywhere other than software on your own machine. listen=1 #enable download of new data This ...
Claris's user avatar
  • 15.4k
2 votes
Accepted

Low number from getconnectioncount

I have been running my bitcoin node for about 24 hours now and I'm hovering at 54 active connections. That's quite high for just 24 hours. However, I thought that I would be at 125. Why is it that I'...
Pieter Wuille's user avatar
2 votes

Why do nodes have a maximum peer count?

Holding the state of a peer and handling its requests consumes resources. Mainly RAM, bandwidth and CPU. Each additional peer has a fixed cost for a node but a decreasing utility.
Antoine Poinsot's user avatar
2 votes

I Can't Get Inbound Connections to My Node

I was unaware that Uncomplicated Firewall ufw was installed on my Raspberry Pi. When I ran the command below I found the following. sudo ufw status verbose Status: active Logging: on (low) Default: ...
jctbtc's user avatar
  • 141
1 vote

Where can I find RPC_User and RPC_Password for my Python Script?

To use this library you need an instance of Bitcoin core! If you start with Bitcoin I suggest you to run an instance of bitcoin core and understand how the config it. You can find a good start here! ...
vincenzopalazzo's user avatar
1 vote
Accepted

How to achieve fast mempool synchronization at startup?

mempoolcp command line utility is what you are looking for: https://github.com/dev7ba/mempoolcp
dev7ba's user avatar
  • 373
1 vote

difference between inbound and outbound connection

When your client start the connection with another peer it is outbound, otherwise it is inbound. If you want to be sure that your tor node is properly setup and that other peer can connect to you, ...
Saxtheowl's user avatar
  • 2,800
1 vote

Are nodes that don't accept inbound connections necessarily leechers?

Non-listening nodes can be considered leechers because they take up available node capacity and don't provide capacity of their own thereby reducing the total number of nodes that can be on the ...
Ava Chow's user avatar
  • 70.4k
1 vote

Can a Bitcoin node create an outgoing connection to a inbound node?

Jan, there is a mechanism that prevents Bitcoin Core from opening a new connection (making an outbound) to an address it is already connected to (irrelevant of whether the existent connection is ...
vasild's user avatar
  • 41
1 vote

Which peers does a node broadcast a new block to?

All peers are treated equally when relaying chain-extending blocks (as James C. stated in a comment on another answer). The node will announce the block to all of its peers and since that block was ...
Murch's user avatar
  • 75.3k
1 vote

Port 8333 and Issues to have a connection

You are conflating the two ports that Bitcoin Core opens and uses. There is the Bitcoin network port. That is port 8333 by default. You DO NOT want to try to connect to that as it is used for the ...
Ava Chow's user avatar
  • 70.4k

Only top scored, non community-wiki answers of a minimum length are eligible