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  • šŸ“šLEARN
    • Introduction
      • šŸ”·1. Ethereum Basics
        • 1.1 Ethereum: Concept, Infrastructure & Purpose
        • 1.2 Properties of the Ethereum Infrastructure
        • 1.3 Ethereum vs. Bitcoin
        • 1.4 Ethereum Core Components
        • 1.5 Gas Metering: Solving the Halting Problem
        • 1.6 web2 vs. web3: The Paradigm Shift
        • 1.7 Decentralization
        • 1.8 Cryptography, Digital Signature & Keys
        • 1.9 Ethereum State & Account Types
        • 1.10 Transactions: Properties & Components
        • 1.11 Contract Creation
        • 1.12 Transactions, Messages & Blockchain
        • 1.13 EVM (Ethereum Virtual Machine) in Depth
        • 1.14 Transaction Reverts & Data
        • 1.15 Block Explorer
        • 1.16 Mainnet & Testnets
        • 1.17 ERCs & EIPs
        • 1.18 Legal Aspects in web3: Pseudonymity & DAOs
        • 1.19 Security in web3
        • 1.20 web2 Timescales vs. web3 Timescales
        • 1.21 Test-in-Prod. SSLDC vs. Audits
        • Summary: 101 Keypoints
      • šŸŒ€2. Solidity
        • 2.1 Solidity: Influence, Features & Layout
        • 2.2 SPDX & Pragmas
        • 2.3 Imports
        • 2.4 Comments & NatSpec
        • 2.5 Smart Contracts
        • 2.6 State Variables: Definition, Visibility & Mutability
        • 2.7 Data Location
        • 2.8 Functions
        • 2.9 Events
        • 2.10 Solidity Typing
        • 2.11 Solidity Variables
        • 2.12 Address Type
        • 2.13 Conversions
        • 2.14 Keywords & Shorthand Operators
        • 2.15 Solidity Units
        • 2.16 Block & Transaction Properties
        • 2.17 ABI Encoding & Decoding
        • 2.18 Error Handling
        • 2.19 Mathematical & Cryptographic Functions
        • 2.20 Control Structures
        • 2.21 Style & Conventions
        • 2.22 Inheritance
        • 2.23 EVM Storage
        • 2.24 EVM Memory
        • 2.25 Inline Assembly
        • 2.26 Solidity Version Changes
        • 2.27 Security Checks
        • 2.28 OpenZeppelin Libraries
        • 2.29 DAppSys Libraries
        • 2.30 Important Protocols
        • Summary: 201 Keypoints
      • šŸ”3. Security Pitfalls & Best Practices
        • 3.1 Solidity Versions
        • 3.2 Access Control
        • 3.3 Modifiers
        • 3.4 Constructor
        • 3.5 Delegatecall
        • 3.6 Reentrancy
        • 3.7 Private Data
        • 3.8 PRNG & Time
        • 3.9 Math & Logic
        • 3.10 Transaction Order Dependence
        • 3.11 ecrecover
        • 3.12 Unexpected Returns
        • 3.13 Ether Accounting
        • 3.14 Transaction Checks
        • 3.15 Delete Mappings
        • 3.16 State Modification
        • 3.17 Shadowing & Pre-declaration
        • 3.18 Gas & Costs
        • 3.19 Events
        • 3.20 Unary Expressions
        • 3.21 Addresses
        • 3.22 Assertions
        • 3.23 Keywords
        • 3.24 Visibility
        • 3.25 Inheritance
        • 3.26 Reference Parameters
        • 3.27 Arbitrary Jumps
        • 3.28 Hash Collisions & Byte Level Issues
        • 3.29 Unicode RTLO
        • 3.30 Variables
        • 3.31 Pointers
        • 3.32 Out-of-range Enum
        • 3.33 Dead Code & Redundant Statements
        • 3.34 Compiler Bugs
        • 3.35 Proxy Pitfalls
        • 3.36 Token Pitfalls
        • 3.37 Special Token Pitfalls
        • 3.38 Guarded Launch Pitfalls
        • 3.39 System Pitfalls
        • 3.40 Access Control Pitfalls
        • 3.41 Testing, Unused & Redundand Code
        • 3.42 Handling Ether
        • 3.43 Application Logic Pitfalls
        • 3.44 Saltzer & Schroeder's Design Principles
        • Summary: 201 Keypoints
      • šŸ—œļø4. Audit Techniques & Tools
        • 4.1 Audit
        • 4.2 Analysis Techniques
        • 4.3 Specification, Documentation & Testing
        • 4.4 False Positives & Negatives
        • 4.5 Security Tools
        • 4.6 Audit Process
        • Summary: 101 Keypoints
      • ā˜ļø5. Audit Findings
        • 5.1 Criticals
        • 5.2 Highs
        • 5.3 Mediums
        • 5.4 Lows
        • 5.5 Informationals
        • Summary: 201 Keypoints
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      • Secureum A-MAZE-X
      • Secureum A-MAZE-X Stanford
      • Secureum A-MAZE-X Maison de la Chimie Paris
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  1. LEARN
  2. Introduction
  3. 1. Ethereum Basics

1.16 Mainnet & Testnets

Mainnet refers to the main Ethereum network. There is a distinction because there also exist several testnets. These testnets are test Ethereum networks where protocol and smart contract developers can test their protocol upgrades and smart contracts prior to final deployment in mainnet.

While mainnet uses real Ether, testnets use what is known as "test Ether'', so that you can simulate the Gas, the transfer of value and so on... These test Ether can be obtained from faucets.

Some of the popular Ethereum testnets are Goerli (a proof of authority testnet that allows one to look at a lot of the Ethereum concepts and test them as if they are happening on mainnet). This particular testnet works across all the clients.It's called proof of authority because there are a small number of nodes that are allowed to create the blocks and validate them. After the Ropsten testnet reached a Terminal Total Difficulty (TTD) of 5Ɨ10165\times 10^{16}5Ɨ1016, the Goerli testnet transitioned to a proof-of-stake consensus mechanism to mimic Ethereum mainnet.

Then we have the Kovan testnet, which is again a proof of authority testnet specifically for those running OpenEthereum clients.

There is also the Sepolia Testnet. Sepolia was a proof-of-authority testnet created in October 2021. Similarly to Goerli, after the Ropsten testnet reached a Terminal Total Difficulty (TTD) of 5Ɨ10165\times 10^{16}5Ɨ1016, the Sepolia testnet transitioned to a proof-of-stake consensus mechanism. Sepolia was designed to simulate harsh network conditions, and has shorter block times, which enable faster transaction confirmation times and feedback for developers. Compared to other testnets like Goerli, Sepolia's total number of testnet tokens is uncapped, which means it is less likely that developers using Sepolia will face testnet token scarcity like Goerli.

As you can see, these testnets are also evolving, new ones are being added over time trying to make it as easy as possible for the developers to simulate the real mainnet Ethereum blockchain and all its dependencies. This again becomes very critical to security because testing is fundamental: if you do not test, or if the testing environment is not very similar to the production environment, then the assumptions (the dependencies and other aspects that are tested) will be very different from what happens when you deploy the contract, which could end up causing a lot of security issues.

Deprecated testnets

Testnets are also removed over time. Some of the deprecated testnets are

  • Rinkeby testnet. It was a proof of authority based testnet which was specifically for the Geth clients. It shut down in 2023.

  • Ropsten testnet. It was a proof of work testnet. It shut down at the end of 2022.

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Last updated 1 year ago

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