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100 votes
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What happens when a transaction nonce is too high?

Summary Transactions with too low a nonce get immediately rejected. Transactions with too high a nonce get placed in the transaction pool queue. If transactions with nonces that fill the gap between ...
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61 votes
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Which TCP and UDP ports are required to run an Ethereum client?

Ethereum clients use a listener (TCP) port and a discovery (UDP) port, both on 30303 by default. If you need to run JSON-RPC, you'll also need TCP port 8545. Note that JSON-RPC port should not be ...
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58 votes
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Why is the average block time 17 seconds?

Due to advances in blockchain research, it was shown that significantly lower block times were possible and perhaps beneficial given the current connectivity of the internet. One of the potential ...
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35 votes

Why is my node synchronization stuck/extremely slow at block 2,306,843?

Update Mar 5 2017 The state cleaning was announced by Vitalik Buterin in the tweet State clearing 100% complete dated 23:07 Nov 29 2016. This time corresponds to block 2,718,436. The Clearing ...
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30 votes
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How many nodes are there on the Ethereum network?

Disclaimer: I run ethernodes.org There is a node explorer available at ethernodes.org which tries to estimate the number of nodes on the Ethereum network. The estimation is based on an active ...
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  • 565
23 votes
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How do Ethereum mining nodes maintain a time consistent with the network?

Ethereum nodes (regardless of mining) need to have an accurate time, otherwise they will not be able to connect to peers and to the network (https://github.com/ethereum/go-ethereum/wiki/Connecting-to-...
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  • 78.8k
22 votes

What is an Enode ID in Ethereum?

An enode is a way to describe an Ethereum node in the form of a URI. The hexadecimal node ID is encoded in the username portion of the URL, separated from the host by an @ sign. The hostname can only ...
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15 votes
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Why is the launch of homestead important?

The Ethereum project originally laid out a timeline of milestones representative of different states of the ecosystem. In brief, they are: Frontier, a "wild west" stage with emphasized user caution ...
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14 votes
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What is an Enode ID in Ethereum?

Expanding on Hudson Jameson's answer: "The hexadecimal node ID is encoded in the username portion of the URL" The username portion is a 512-bit public key that is used to verify communication came ...
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14 votes
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Why doesn't my Ethereum node have any peers?

By default, geth uses port 30303 for connection to other nodes. You may need to modify your firewall to allow traffic over this port. You can check your peer count as well as getting a list of peers ...
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14 votes
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How fast should be an internet connection to mine ETH?

How fast should be an internet connection to mine ETH? I'm currently on a ~ 10 Mbits/s download and 1 Mbits/s upload line and it is fast enough to mine the Ethereum blockchain while performing my ...
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12 votes
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How to ask the metamask user to switch its network?

Here is an example how to make your website to ask the users so they can add and switch to the Matic network: window.ethereum.request({ method: "wallet_addEthereumChain", params: [{ ...
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11 votes
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How to prevent being blacklisted for running an ethereum client?

You can tell parity to avoid scanning private IPs by simply running: parity --allow-ips public You can even fine-tune parity to do less aggressive peering: parity --allow-ips public --no-discovery -...
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11 votes
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At any given time, how many nodes is my node connected to? As the number of nodes in the network increases, will communication between them be faster?

You can see the connected peers by typing admin.peers in the Geth console. The maximum number of peers is set using the -maxpeers n flag in Geth. There is a discovery process based on Kademlia for ...
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  • 3,282
8 votes

How many nodes are there on the Ethereum network?

There are two tools which track running ether nodes available: The etherchain node scanner. The ethernodes scanner.
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  • 31.5k
8 votes
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Is there a point to hide Ethereum nodes with TOR?

If you want to conceal your node's network address as the source of your transaction, and thereby preventing others to associate your network address with your Ethereum address, then you might want to ...
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8 votes
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How to connect an ethereum node to a random testnet?

For Geth you can connect to the public testnet (Morden) via: geth --testnet For other clients and for a full explanation plese refer to this wiki page: Ethereum wiki / Morden If you don't want to ...
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  • 2,331
8 votes
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Peer discovery not working on private network

Each of the geth instances will need to discover at least one other instance with a connection to the rest of your private network. You could nominate one (or more) of your geth instances as a ...
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8 votes

How do Ethereum mining nodes maintain a time consistent with the network?

Here's the code I've found so far that deals with syncing time. It uses pool.ntp.org:123 as the time syncing source. From Go Ethereum - p2p/discover/ntp.go, lines 48-65: func checkClockDrift() { ...
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8 votes

Why is my node synchronization stuck/extremely slow at block 2,306,843?

On a practical note, just remove your blockchain and synchronize again. The blockchain bloat has been removed already. Stop your node and/or close your Ethereum wallet. Remove the chaindata. for ...
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7 votes
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How to connect NodeJS to the Ethereum network?

Ethereum offers a Web3 JavaScript Ðapp API To make your Ðapp work on Ethereum, you can use the web3 object provided by the web3.js library. Under the hood it communicates to a local node through ...
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  • 9,403
7 votes
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Ethereum fork of OpenBazaar

Keep an eye on Safemarket.io: it is already deployed live on the Frontier network. See getting started and releases. Open source at https://github.com/safemarket Subreddit at https://reddit.com/r/...
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  • 78.8k
7 votes

Losing connection between nodes on private network

Summary I would have expected that the bootnodes parameters would allow node 2 and node 3 to find node 1, node 2 and node 3 and then for all the nodes to retain their peer connections. From Henrique ...
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7 votes

How fast should be an internet connection to mine ETH?

Mining itself doesn't use that much bandwidth, however syncing the block chain does. For syncing the blockchain using the --fast option it used about 12Gb(Initial sync) and about 100 mb the past 2 ...
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  • 312
7 votes
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Is it possible to prevent nodes from mining on a private blockchain?

What you are searching for is a permissioned blockchain. Default node clients like geth, eth or pyehtereum does not implement this kind of functionality, so you need something more complex that ...
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7 votes

How to prevent being blacklisted for running an ethereum client?

I had a similar problem like you. Hetzner noticed that the abuse warning was triggered because the host tried to send tpc/udp packets to private network addresses (RFC1918). In order to avoid getting ...
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  • 7,194
6 votes

network port udp:30303 could not be mapped: no UPnP or NAT-PMP router discovered

On some rare setups UPnP lookup fails in a strange way that blocks up Geth. It was already fixed on develop and will hopefully land soon. Until that point if you experience this you might disable NAT ...
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6 votes

How many nodes are there on the Ethereum network?

Update. As of this morning (July 31, 2017), there were 21,349 nodes, according to Ethernodes. The Etherchain Node scanner which 5chdn listed as the other nodes tracker in his Feb. 2016 answer (https://...
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  • 2,249
6 votes
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Are there any alternative programmable networks to Ethereum?

Rootstock would be the main example, check out their site for more info http://www.rootstock.io/ They use bitcoin instead of using their own coin, but they are not as far along with the smart ...
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6 votes

How does Ethereum client select which peers to synchronise with?

Only a partial answer for the first couple of sub-questions... How many nodes do we connect to? The maximum number is set to 25 by default, but can be configured using the --maxpeers flag on the ...
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