Building a Private Ethereum PoA Network with Geth 1.13.14

This guide walks you through setting up a private Ethereum network using Proof of Authority (PoA) consensus with Go Ethereum (Geth) 1.13.14. Perfect for developers looking to experiment with blockchain technology or create a controlled environment for testing smart contracts.

Prerequisites

• Go Language (v1.22.0 or later)
• Go Ethereum (Geth v1.13.14-stable)
• Your preferred code editor (VSCode recommended)

Installation

Installing Go

# For Ubuntu/Debian
sudo apt-get update
sudo apt-get install golang-go

# Verify installation
go version

Installing Geth

# For Ubuntu/Debian
sudo add-apt-repository -y ppa:ethereum/ethereum
sudo apt-get update
sudo apt-get install ethereum

# Verify installation
geth version

Setting Up Your Private Network

1. Create Project Structure

# Create main project directory
mkdir ethereum-poa-network
cd ethereum-poa-network

# Create folders for each node and bootnode
mkdir node1 node2 bnode

# Create info file to track account details
touch info.txt

2. Create Accounts for Your Nodes

# Navigate to the first node directory
cd node1

# Create new account
geth --datadir "./data" account new
# Save the address and password in info.txt

# Navigate to the second node directory
cd ../node2

# Create new account
geth --datadir "./data" account new
# Save the address and password in info.txt

3. Create Configuration File

Create a file named privateblock.json in the project root with the following content:

{
  "config": {
    "chainId": 1234567,
    "homesteadBlock": 0,
    "eip150Block": 0,
    "eip155Block": 0,
    "eip158Block": 0,
    "byzantiumBlock": 0,
    "constantinopleBlock": 0,
    "petersburgBlock": 0,
    "istanbulBlock": 0,
    "berlinBlock": 0,
    "clique": {
      "period": 5,
      "epoch": 30000
    }
  },
  "difficulty": "1",
  "gasLimit": "8000000",
  "extradata": "0x0000000000000000000000000000000000000000000000000000000000000000NODE1_ADDRESS_WITHOUT_0X0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
  "alloc": {
    "NODE1_ADDRESS_WITHOUT_0X": {
      "balance": "3000000000000000000000000000000000000"
    },
    "NODE2_ADDRESS_WITHOUT_0X": {
      "balance": "3000000000000000000000000000000000000"
    }
  }
}

Replace NODE1_ADDRESS_WITHOUT_0X and NODE2_ADDRESS_WITHOUT_0X with your node account addresses (remove the leading "0x").

4. Initialize Nodes with Genesis Block

# Initialize node1
cd node1
geth --datadir ./data init ../privateblock.json

# Initialize node2
cd ../node2
geth --datadir ./data init ../privateblock.json

5. Set Up Bootnode

# Navigate to bootnode directory
cd ../bnode

# Generate bootnode key
bootnode -genkey boot.key

# Start the bootnode
bootnode -nodekey boot.key -verbosity 7 -addr "127.0.0.1:30301"

Save the enode URL that appears in the terminal to your info.txt file.

6. Create Password Files

Create a password.txt file in each node directory containing only the password for that node's account.

# For node1
echo "your_node1_password" > node1/password.txt

# For node2
echo "your_node2_password" > node2/password.txt

7. Start the Signer Node (Node1)

cd node1
geth --datadir "./data" --port 30304 --bootnodes "BOOTNODE_ENODE_URL" --authrpc.port 8547 --ipcdisable --allow-insecure-unlock --http --http.corsdomain="https://remix.ethereum.org" --http.api web3,eth,debug,personal,net --networkid 1234567 --unlock "NODE1_ADDRESS" --password password.txt --mine --miner.etherbase="NODE1_ADDRESS"

Replace:

• BOOTNODE_ENODE_URL with your bootnode's enode URL
• NODE1_ADDRESS with your first node's account address (with 0x prefix)

8. Start the Second Node (Node2)

Open a new terminal window and run:

cd node2
geth --datadir "./data" --port 30306 --bootnodes "BOOTNODE_ENODE_URL" --authrpc.port 8546 --ipcdisable --http --http.port 8546 --http.corsdomain="https://remix.ethereum.org" --http.api web3,eth,debug,personal,net --networkid 1234567 --unlock "NODE2_ADDRESS" --password password.txt

Replace:

• BOOTNODE_ENODE_URL with your bootnode's enode URL
• NODE2_ADDRESS with your second node's account address (with 0x prefix)

Connecting to Your Network

Using Remix IDE

1. Open Remix IDE
2. Go to the "Deploy & Run Transactions" tab
3. In the Environment dropdown, select "Custom - External HTTP Provider"
4. Enter http://127.0.0.1:8545 (for node1) or http://127.0.0.1:8546 (for node2)
5. Click "OK"

You can now deploy and interact with smart contracts on your private network.

Using Web3.js or ethers.js

Connect to your private network using the JSON-RPC endpoint:

• Node1: http://127.0.0.1:8545
• Node2: http://127.0.0.1:8546

Troubleshooting

Port Conflicts

If you see an error like "listen tcp :30304: bind: Only one usage of each socket address is normally permitted", change the port numbers to avoid conflicts.

Account Unlock Issues

If you encounter "Failed to unlock account" errors, verify:

• The account exists in the keystore directory
• The password in password.txt is correct
• You're using the right account address

Network Synchronization

If nodes aren't connecting:

• Verify bootnode is running
• Check if the enode URL is correct
• Ensure the chainId/networkid matches between nodes

Advanced Configuration

Adding Custom CORS Domains

To allow access from custom domains or local development servers:

--http.corsdomain="https://remix.ethereum.org,http://127.0.0.1:8000,http://localhost:3000"

Monitoring Your Network

You can attach a JavaScript console to a running node:

geth attach http://127.0.0.1:8545

Inside the console, check peer connections:

net.peerCount
admin.peers

Resources

• Go Ethereum Documentation
• Clique PoA Consensus Explanation
• Remix IDE