[Ethereum] Private chain Ethereum handshake failed Genesis block mismatch

genesisgo-ethereumprivate-blockchain

I'm setting up a private chain between two VMs.

The first node started mining successfully, and the connetion between the two VMs has no problem.

But when I try to connect the second node to the first, I got this error:

DEBUG[05-08|09:21:11] Ethereum handshake failed
id=e8d86dae37655a1b conn=dyndial err="Genesis block mismatch –
dfc3e94e54007bba (!= 573969da5d11c81a)"

I copied the genesis.json file from the first node to the second, how can they mismatch?

The command I used to start the first node is:

geth --identity nodeBcDev1 --nodiscover --networkid 9191 --port 60830 --maxpeers 5 --lightkdf --cache 512 --rpc --rpccorsdomain "*" --datadir "C:\BlockChain\Data" --minerthreads 2 --mine

The command to connect from the second node:

geth --networkid 9191 --port 60830 --rpc --rpcport 8545 --rpccorsdomain "*" --datadir "C:\BlockChain\Data" --minerthreads 2 --bootnodes "enode://41cc17dydeefide8018c39054653d638430c3abfe3f77g009dc9294h0e8a9d62a5b819fb5810391fddab560d4c1bf9d1c9b110c6fbe603731388a993751bd95e@10.0.0.1:60830" --verbosity 4

Finally, the genesis.json file:

{
    "nonce"         : "0x0000000000000055",
    "mixHash"       : "0x0000000000000000000000000000000000000000000000000000000000000000",
    "parentHash"    : "0x0000000000000000000000000000000000000000000000000000000000000000",
    "difficulty"    : "0x1",
    "gasLimit"  : "0x800000",
    "timestamp" : "0x0",
    "extraData" : "",
    "coinbase"  : "0x0000000000000000000000000000000000000000",
    "alloc"         : {},
    "config"    : {
        "chainId": 9191,
        "homesteadBlock": 0,
        "eip155Block": 0,
        "eip158Block": 0
    }
}

My client id matches the network id, and I know the connection was successful because the lines above the handshake failure was:

DEBUG[05-08|09:21:11] Ethereum peer connected                  id=df887467936a7c9b conn=dyndial name=Geth/v1.8.0-unstable/linux-amd64/go1.9.4

Really confused…..

Best Answer

This is common issue for setting up local network. There are major four issues can stop syncing blocks.

Mismatching genesis block.
Didn't added boot node.
Network id is mismatch.
Unable to access node system

How to check your genesis block is same for two or more nodes?

Type below command in your geth consle.

> admin.nodeInfo.protocols.eth.genesis

0x981XXXXXXXXXXXxxxxxxxxXXXXXXXxxxxxXXXXxxxxXXXXXxxxXXx Join two nodes two genesis file should match. If its not matched geth node will reject connect, because of replay attack. i.e you need to init your nodes with same genesis.json. Please don't edit genesis.json

--nodiscover:

When you use this option your node will not be exposed to outside system to scan. Then how to add this node to an other node, use --bootnodes or admin.addPeer('');

Network id is mismatch

While running your geth node your network id may be mismatch, or you may forgot to add. use --networkid at time of geth command.

Unable to access node system

Due to some network firewalls settings, your port is not accessible. Like AWS you need to add tcp port to be enabled for EC2 instance.

For more details please refer below link: https://medium.com/mercuryprotocol/how-to-create-your-own-private-ethereum-blockchain-dad6af82fc9f

Related Solutions

[Ethereum] Fatal: failed to write genesis block: wrong genesis block in database

You cannot do a init again if you have already done a init on datadir. In order to achive what you want you need to first create simply create account .... once account is created use that for pre-funding, by putting it in the genesis file, now go for the init of datadir.

so steps are
1) Creation of account in datadir

geth --datadir <path_of_data_directory> account new ( I have used command line method for account creation, which does not require invocation of geth console)

2) use the account created as pre-funded account, add entry in genesis file.

3) Init of the datadirectory with the genesis file.

geth --datadir <path_of_data_directory> init <path_of_genesis_file>

I have used bare minimum parameters, it should also work fine with the parameter you are using. Main point to note you cannot re-initialize your data directory once it is initialized.

[Ethereum] How to generate the correct go-ethereum bootnode when creating a private blockchain

If you can't telnet then there is something wrong with your networking. Either your virtual network connection between hosts is the problem or there is a firewall blocking connections.

If you are just getting started then I'd keep things really simple first of all and:

Use standard geth nodes
Run your nodes on one virtual machine on different ports

e.g. initialise your geth nodes like this:

ethuser@host01:~$ mkdir test1
ethuser@host01:~$ cd test1
ethuser@host01:~/test1$ mkdir nodeA
ethuser@host01:~/test1$ mkdir nodeB
ethuser@host01:~/test1$ <use your favourite editor to create a genesis.json file in this directory>
ethuser@host01:~/test1$ geth --datadir nodeA init genesis.json
WARN [08-04|10:41:41] No etherbase set and no accounts found as default 
INFO [08-04|10:41:41] Allocated cache and file handles         database=/home/ethuser/test1/nodeA/geth/chaindata cache=16 handles=16
INFO [08-04|10:41:41] Writing custom genesis block 
INFO [08-04|10:41:41] Successfully wrote genesis state         database=chaindata                                hash=dd3f8d…707d0d
INFO [08-04|10:41:41] Allocated cache and file handles         database=/home/ethuser/test1/nodeA/geth/lightchaindata cache=16 handles=16
INFO [08-04|10:41:41] Writing custom genesis block 
INFO [08-04|10:41:41] Successfully wrote genesis state         database=lightchaindata                                hash=dd3f8d…707d0d
ethuser@host01:~/test1$ geth --datadir nodeB init genesis.json
WARN [08-04|10:41:52] No etherbase set and no accounts found as default 
INFO [08-04|10:41:52] Allocated cache and file handles         database=/home/ethuser/test1/nodeB/geth/chaindata cache=16 handles=16
INFO [08-04|10:41:52] Writing custom genesis block 
INFO [08-04|10:41:52] Successfully wrote genesis state         database=chaindata                                hash=dd3f8d…707d0d
INFO [08-04|10:41:52] Allocated cache and file handles         database=/home/ethuser/test1/nodeB/geth/lightchaindata cache=16 handles=16
INFO [08-04|10:41:52] Writing custom genesis block 
INFO [08-04|10:41:52] Successfully wrote genesis state         database=lightchaindata                                hash=dd3f8d…707d0d
ethuser@host01:~/test1$

Then launch your first geth node like this

ethuser@host01:~/test1$ geth --datadir nodeA --networkid 1234567 console
WARN [08-04|10:42:22] No etherbase set and no accounts found as default 
INFO [08-04|10:42:22] Starting peer-to-peer node               instance=Geth/v1.6.7-stable-ab5646c5/linux-amd64/go1.8.1
INFO [08-04|10:42:22] Allocated cache and file handles         database=/home/ethuser/test1/nodeA/geth/chaindata cache=128 handles=1024
WARN [08-04|10:42:22] Upgrading chain database to use sequential keys 
INFO [08-04|10:42:22] Initialised chain configuration          config="{ChainID: 1907 Homestead: 0 DAO: <nil> DAOSupport: false EIP150: <nil> EIP155: 0 EIP158: 0 Metropolis: <nil> Engine: unknown}"
INFO [08-04|10:42:22] Disk storage enabled for ethash caches   dir=/home/ethuser/test1/nodeA/geth/ethash count=3
INFO [08-04|10:42:22] Disk storage enabled for ethash DAGs     dir=/home/ethuser/.ethash                 count=2
WARN [08-04|10:42:22] Upgrading db log bloom bins 
INFO [08-04|10:42:22] Bloom-bin upgrade completed              elapsed=252.683µs
INFO [08-04|10:42:22] Initialising Ethereum protocol           versions="[63 62]" network=1234567
INFO [08-04|10:42:22] Database conversion successful 
INFO [08-04|10:42:22] Loaded most recent local header          number=0 hash=dd3f8d…707d0d td=40
INFO [08-04|10:42:22] Loaded most recent local full block      number=0 hash=dd3f8d…707d0d td=40
INFO [08-04|10:42:22] Loaded most recent local fast block      number=0 hash=dd3f8d…707d0d td=40
INFO [08-04|10:42:22] Starting P2P networking 
INFO [08-04|10:42:22] UDP listener up                          self=enode://9ce583f7e1905b23217cd2a92894291c6d8f5ce7a29e85fdeaf48b3ab065c6d5b6cce4f064fdaf26f41d2354bf0a203438563f6ffdba73cec3b8692f6f850817@[::]:30303
INFO [08-04|10:42:22] RLPx listener up                         self=enode://9ce583f7e1905b23217cd2a92894291c6d8f5ce7a29e85fdeaf48b3ab065c6d5b6cce4f064fdaf26f41d2354bf0a203438563f6ffdba73cec3b8692f6f850817@[::]:30303
INFO [08-04|10:42:22] IPC endpoint opened: /home/ethuser/test1/nodeA/geth.ipc 
Welcome to the Geth JavaScript console!

instance: Geth/v1.6.7-stable-ab5646c5/linux-amd64/go1.8.1
 modules: admin:1.0 debug:1.0 eth:1.0 miner:1.0 net:1.0 personal:1.0 rpc:1.0 txpool:1.0 web3:1.0

>

And then start up your second node. In my case I needed to use ethuser@host01:~/test1$ geth --datadir nodeB --port 30304 --networkid 1234567 --bootnodes enode://9ce583f7e1905b23217cd2a92894291c6d8f5ce7a29e85fdeaf48b3ab065c6d5b6cce4f064fdaf26f41d2354bf0a203438563f6ffdba73cec3b8692f6f850817@127.0.0.1:30303

Wait a few moments to give the nodes a chance to connect and then double check in your console that admin.peers returns some more info, e.g.

> admin.peers
[{
    caps: ["eth/63"],
    id: "9ce583f7e1905b23217cd2a92894291c6d8f5ce7a29e85fdeaf48b3ab065c6d5b6cce4f064fdaf26f41d2354bf0a203438563f6ffdba73cec3b8692f6f850817",
    name: "Geth/v1.6.7-stable-ab5646c5/linux-amd64/go1.8.1",
    network: {
      localAddress: "127.0.0.1:41900",
      remoteAddress: "127.0.0.1:30303"
    },
    protocols: {
      eth: {
        difficulty: 40,
        head: "0xdd3f8d61f38ebc195a6c9b0e5888e7e035f31ecd92e4427fb01176b984707d0d",
        version: 63
      }
    }
}]
>

I've left out creating accounts etc as you don't specifically ask it but if you're interested here are some more of my own newbie experiences: https://alanbuxton.wordpress.com/2017/07/19/first-steps-with-ethereum-private-networks-and-smart-contracts-on-ubuntu-16-04/

Best Answer

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[Ethereum] Fatal: failed to write genesis block: wrong genesis block in database

[Ethereum] How to generate the correct go-ethereum bootnode when creating a private blockchain

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