ChainId was introduced to prevent double-spending attacks. The Network ID (NetworkID) primarily serves as a network-layer identifier for blockchain networks. Nodes with mismatched NetworkIDs cannot establish connections.
After Ethereum Classic forked from Ethereum, ChainID was introduced via EIP155 to prevent replay attacks. By including ChainID in transaction signatures, a signed transaction cannot be resubmitted on different chains.
Ethereum Network IDs
Ethereum uses distinct IDs for its mainnet and test networks:
Mainnet (Ethereum Main Network)
- Network ID:
1 - Chain ID:
1
Ropsten (Proof-of-Work Testnet)
- Network ID:
3 - Chain ID:
3
Rinkeby (Proof-of-Authority Testnet)
- Network ID:
4 - Chain ID:
4
Goerli (Proof-of-Authority Testnet)
- Network ID:
5 - Chain ID:
5
Kovan (Proof-of-Authority Testnet)
- Network ID:
42 - Chain ID:
42
Ethereum Classic Mainnet
- Network ID:
1 - Chain ID:
61
Morden (Ethereum Classic Testnet)
- Network ID:
2 - Chain ID:
62
Extended Ethereum-Compatible Networks
Many platforms now host Ethereum-compatible chains. Below is a curated list of ChainIDs sourced from ChainID Network:
| Chain ID | Network Name | Short Name | Symbol | Network Type |
|----------|----------------------------|------------|--------|--------------|
| 1 | Ethereum Mainnet | ETH | ETH | Mainnet |
| 10 | Optimistic Ethereum | OETH | ETH | Mainnet |
| 56 | Binance Smart Chain | BNB | BSC | Mainnet |
| 100 | xDAI Chain | xDAI | XDAI | Mainnet |
| 137 | Polygon (Matic) Mainnet | MATIC | MATIC | Mainnet |
| 246 | Energy Web Chain | EWT | EWC | Mainnet |
| 42161| Arbitrum One | ARB | ETH | Mainnet |
👉 Explore Ethereum-compatible networks
FAQ
Why is ChainID important?
ChainID prevents transaction replay attacks by ensuring transactions signed for one network cannot be reused on another.
What happens if nodes have different NetworkIDs?
Nodes with mismatched NetworkIDs cannot communicate, ensuring network isolation.
How does Ethereum Classic differ from Ethereum in ChainID?
Ethereum Classic uses ChainID 61, while Ethereum Mainnet uses ChainID 1 to avoid cross-chain transaction conflicts.
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