Part 1.8: Practical Lab - Setting Up a Blockchain Node

Lab Overview

In this hands-on lab, you'll gain practical experience setting up and configuring blockchain nodes. You'll work with both Bitcoin and Ethereum test networks to understand node operation, blockchain synchronization, and basic interaction with the network.

Important: Use Test Networks Only

This lab uses testnet environments where cryptocurrency has no real value. Never use mainnet for learning exercises, as mistakes could result in financial loss.

System Requirements

💻

CPU

4+ cores recommended

💾

RAM

8GB minimum, 16GB recommended

📁

Storage

100GB+ SSD for testnet

🌐

Network

Stable broadband connection

Lab 1: Running a Bitcoin Testnet Node

1

Download Bitcoin Core

Download Bitcoin Core from the official website (bitcoin.org). Verify the download signature to ensure authenticity.

                        Download and verify
                        Terminal
                    

# Download Bitcoin Core (example for Linux)
wget https://bitcoin.org/bin/bitcoin-core-25.0/bitcoin-25.0-x86_64-linux-gnu.tar.gz

# Verify SHA256 checksum
sha256sum bitcoin-25.0-x86_64-linux-gnu.tar.gz

# Extract
tar -xvf bitcoin-25.0-x86_64-linux-gnu.tar.gz
                    

2

Configure for Testnet

Create a configuration file to run in testnet mode with appropriate settings.

                        bitcoin.conf
                        Config
                    

# Run on testnet
testnet=1

# Enable RPC server
server=1
rpcuser=yourusername
rpcpassword=yourpassword

# Data directory (optional)
datadir=/path/to/bitcoin/data

# Reduce resource usage for testing
dbcache=450
maxmempool=300
                    

3

Start the Node

                        Start Bitcoin daemon
                        Terminal
                    

# Start the daemon
./bitcoind -daemon

# Check sync status
./bitcoin-cli -testnet getblockchaininfo

# View connected peers
./bitcoin-cli -testnet getpeerinfo
                    

Lab 2: Running an Ethereum Sepolia Node

1

Install Geth (Go Ethereum)

                        Install Geth
                        Terminal
                    

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

# Verify installation
geth version
                    

2

Start Sepolia Testnet Node

                        Run Geth on Sepolia
                        Terminal
                    

# Start Geth on Sepolia testnet with sync mode
geth --sepolia --http --http.api eth,net,web3

# Attach to running node
geth attach http://localhost:8545

# Check sync status (in console)
> eth.syncing
> eth.blockNumber
                    

3

Interact with the Network

                        Geth JavaScript Console
                        Console
                    

// Get current block number
> eth.blockNumber

// Get network peer count
> net.peerCount

// Get gas price
> eth.gasPrice

// Create a new account
> personal.newAccount("your-password")
                    

Lab Exercises

Exercise 1: Monitor Blockchain Sync

Start your node and monitor the synchronization process. Note the initial block download time, sync progress, and network bandwidth usage. Document how long it takes to sync the testnet.

Exercise 2: Explore the Blockchain

Use RPC commands to explore recent blocks. Find the hash of the latest block, count the transactions in it, and examine a specific transaction's details.

Exercise 3: Get Testnet Tokens

Create a wallet address and obtain testnet tokens from a faucet. Send a test transaction between two addresses you control and verify it on a block explorer.

Lab Takeaways

Running a full node requires significant resources - storage for blockchain data, bandwidth for syncing, and consistent uptime.
Initial blockchain sync can take hours to days depending on network, hardware, and sync mode (full vs. light).
RPC interfaces enable programmatic interaction with the blockchain for building applications.
Always use testnets for learning - mistakes on mainnet can be costly and irreversible.