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Create a permissioned network

The following steps set up a permissioned network with local node and account permissions. The network uses the IBFT 2.0 proof of authority consensus protocol.

danger

A permissioned Ethereum network as described here is not protected against all attack vectors. We recommend applying defense in depth to protect your infrastructure.

Prerequisites​

Steps​

1. Create folders​

Each node requires a data directory for the blockchain data.

Create directories for your permissioned network and each of the three nodes, and a data directory for each node:

Permissioned-Network/
├── Node-1
│   ├── data
├── Node-2
│   ├── data
└── Node-3
│   ├── data
└── Node-4
    ├── data

2. Create the configuration file​

The configuration file defines the IBFT 2.0 genesis file and the number of node key pairs to generate.

The configuration file has two nested JSON nodes. The first is the genesis property defining the IBFT 2.0 genesis file, except for the extraData string, which Besu generates automatically in the resulting genesis file. The second is the blockchain property defining the number of key pairs to generate.

Copy the following configuration file definition to a file called ibftConfigFile.json and save it in the Permissioned-Network directory:

{
  "genesis": {
    "config": {
      "chainId": 1337,
      "berlinBlock": 0,
      "ibft2": {
        "blockperiodseconds": 2,
        "epochlength": 30000,
        "requesttimeoutseconds": 4
      }
    },
    "nonce": "0x0",
    "timestamp": "0x58ee40ba",
    "gasLimit": "0x47b760",
    "difficulty": "0x1",
    "mixHash": "0x63746963616c2062797a616e74696e65206661756c7420746f6c6572616e6365",
    "coinbase": "0x0000000000000000000000000000000000000000",
    "alloc": {
      "fe3b557e8fb62b89f4916b721be55ceb828dbd73": {
        "privateKey": "8f2a55949038a9610f50fb23b5883af3b4ecb3c3bb792cbcefbd1542c692be63",
        "comment": "private key and this comment are ignored.  In a real chain, the private key should NOT be stored",
        "balance": "0xad78ebc5ac6200000"
      },
      "627306090abaB3A6e1400e9345bC60c78a8BEf57": {
        "privateKey": "c87509a1c067bbde78beb793e6fa76530b6382a4c0241e5e4a9ec0a0f44dc0d3",
        "comment": "private key and this comment are ignored.  In a real chain, the private key should NOT be stored",
        "balance": "90000000000000000000000"
      },
      "f17f52151EbEF6C7334FAD080c5704D77216b732": {
        "privateKey": "ae6ae8e5ccbfb04590405997ee2d52d2b330726137b875053c36d94e974d162f",
        "comment": "private key and this comment are ignored.  In a real chain, the private key should NOT be stored",
        "balance": "90000000000000000000000"
      }
    }
  },
  "blockchain": {
    "nodes": {
      "generate": true,
      "count": 4
    }
  }
}
Security warning

Don't use the accounts in the genesis file on Mainnet or any public network except for testing. The private keys display, which means the accounts are not secure.

3. Generate node keys and a genesis file​

In the Permissioned-Network directory, generate the node key and genesis file:

besu operator generate-blockchain-config --config-file=ibftConfigFile.json --to=networkFiles --private-key-file-name=key

Besu creates the following in the networkFiles directory:

  • genesis.json - The genesis file including the extraData property specifying the four nodes are validators.
  • A directory for each node named using the node address and containing the public and private key for each node.
networkFiles/
├── genesis.json
└── keys
    ├── 0x438821c42b812fecdcea7fe8235806a412712fc0
    │   ├── key
    │   └── key.pub
    ├── 0xca9c2dfa62f4589827c0dd7dcf48259aa29f22f5
    │   ├── key
    │   └── key.pub
    ├── 0xcd5629bd37155608a0c9b28c4fd19310d53b3184
    │   ├── key
    │   └── key.pub
    └── 0xe96825c5ab8d145b9eeca1aba7ea3695e034911a
        ├── key
        └── key.pub

4. Copy the genesis file to the Permissioned-Network directory​

Copy the genesis.json file to the Permisssioned-Network directory.

5. Copy the node private keys to the node directories​

For each node, copy the key files to the data directory for that node

Permissioned-Network/
├── genesis.json
├── Node-1
│   ├── data
│   │    ├── key
│   │    ├── key.pub
├── Node-2
│   ├── data
│   │    ├── key
│   │    ├── key.pub
├── Node-3
│   ├── data
│   │    ├── key
│   │    ├── key.pub
├── Node-4
│   ├── data
│   │    ├── key
│   │    ├── key.pub

6. Create the permissions configuration file​

The permissions configuration file defines the nodes and accounts allowlists.

Copy the following permissions configuration to a file called permissions_config.toml and save a copy in the Node-1/data, Node-2/data, Node-3/data, and Node-4/data directories:

permissions_config.toml
accounts-allowlist=["0xfe3b557e8fb62b89f4916b721be55ceb828dbd73", "0x627306090abaB3A6e1400e9345bC60c78a8BEf57"]

nodes-allowlist=[]

The permissions configuration file includes the first two accounts from the genesis file.

Use the perm_addNodesToAllowlist JSON-RPC API method to add permissioned nodes after starting the nodes.

7. Start Node-1​

Use the following command:

besu --data-path=data --genesis-file=../genesis.json --permissions-nodes-config-file-enabled --permissions-accounts-config-file-enabled --rpc-http-enabled --rpc-http-api=ADMIN,ETH,NET,PERM,IBFT --host-allowlist="*" --rpc-http-cors-origins="*"

The command line allows you to enable:

When the node starts, the enode URL displays. You need the enode URL to specify Node-1 as a peer and update the permissions configuration file in the following steps.

Node 1 Enode URL

8. Start Node-2​

Start another terminal, change to the Node-2 directory, and start Node-2:

besu --data-path=data --genesis-file=../genesis.json --permissions-nodes-config-file-enabled --permissions-accounts-config-file-enabled --rpc-http-enabled --rpc-http-api=ADMIN,ETH,NET,PERM,IBFT --host-allowlist="*" --rpc-http-cors-origins="*" --p2p-port=30304 --rpc-http-port=8546

The command line specifies:

When the node starts, the enode URL displays. You need the enode URL to update the permissions configuration file in the following steps.

9. Start Node-3​

Start another terminal, change to the Node-3 directory, and start Node-3:

besu --data-path=data --genesis-file=../genesis.json --permissions-nodes-config-file-enabled --permissions-accounts-config-file-enabled --rpc-http-enabled --rpc-http-api=ADMIN,ETH,NET,PERM,IBFT --host-allowlist="*" --rpc-http-cors-origins="*" --p2p-port=30305 --rpc-http-port=8547

The command line specifies:

  • A different port to Node-1 and Node-2 for P2P discovery using --p2p-port.
  • A different port to Node-1 and Node-2 for HTTP JSON-RPC using --rpc-http-port.
  • A data directory for Node-3 using --data-path.
  • Other options as for Node-1.

When the node starts, the enode URL displays. You need the enode URL to update the permissions configuration file in the following steps.

10. Start Node-4​

Start another terminal, change to the Node-4 directory, and start Node-4:

besu --data-path=data --genesis-file=../genesis.json --permissions-nodes-config-file-enabled --permissions-accounts-config-file-enabled --rpc-http-enabled --rpc-http-api=ADMIN,ETH,NET,PERM,IBFT --host-allowlist="*" --rpc-http-cors-origins="*" --p2p-port=30306 --rpc-http-port=8548

The command line specifies:

  • A different port to Node-1, Node-2, and Node-3 for P2P discovery using --p2p-port.
  • A different port to Node-1, Node-2, and Node-3 for HTTP JSON-RPC using --rpc-http-port.
  • A data directory for Node-4 using --data-path.
  • Other options as for Node-1.

When the node starts, the enode URL displays. You need the enode URL to update the permissions configuration file in the following steps.

11. Add enode URLs for nodes to permissions configuration file​

Start another terminal and use the perm_addNodesToAllowlist JSON-RPC API method to add the nodes to the permissions configuration file for each node.

Replace <EnodeNode1>, <EnodeNode2>, <EnodeNode3>, and <EnodeNode4> with the enode URL displayed when starting each node.

curl -X POST --data '{"jsonrpc":"2.0","method":"perm_addNodesToAllowlist","params":[["<EnodeNode1>","<EnodeNode2>","<EnodeNode3>","EnodeNode4"]], "id":1}' http://127.0.0.1:8545
tip

The curl call is the same for each node except for the JSON-RPC endpoint.

12. Add nodes as peers​

Use the admin_addPeer JSON-RPC API method to add Node-1 as a peer for Node-2, Node-3, and Node-4.

Replace <EnodeNode1> with the enode URL displayed when starting Node-1.

curl -X POST --data '{"jsonrpc":"2.0","method":"admin_addPeer","params":["<EnodeNode1>"],"id":1}' http://127.0.0.1:8546
tip

The curl call is the same for each node except for the JSON-RPC endpoint.

Replace <EnodeNode2> with the enode URL displayed when starting Node-2.

curl -X POST --data '{"jsonrpc":"2.0","method":"admin_addPeer","params":["<EnodeNode2>"],"id":1}' http://127.0.0.1:8547

Replace <EnodeNode3> with the enode URL displayed when starting Node-3.

curl -X POST --data '{"jsonrpc":"2.0","method":"admin_addPeer","params":["<EnodeNode3>"],"id":1}' http://127.0.0.1:8548

13. Confirm permissioned network is working​

Check peer count​

Use curl to call the JSON-RPC API net_peerCount method and confirm the nodes are functioning as peers:

curl -X POST --data '{"jsonrpc":"2.0","method":"net_peerCount","params":[],"id":1}' localhost:8545

The result confirms Node-1 (the node running the JSON-RPC service) has three peers (Node-2, Node-3 and Node-4):

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x3"
}

Send a transaction from an account in the allowlist​

Import the first account from the genesis file into MetaMask and send transactions, as described in the Quickstart tutorial:

Account 1
  • Address: 0xfe3b557e8fb62b89f4916b721be55ceb828dbd73
  • Private key : 0x8f2a55949038a9610f50fb23b5883af3b4ecb3c3bb792cbcefbd1542c692be63
  • Initial balance : 0xad78ebc5ac6200000 (200000000000000000000 in decimal)
info

Besu doesn't support private key management.

Try sending a transaction from an account not in the accounts allowlist​

Import the third account from the genesis file into MetaMask and try to send a transaction, as described in the Quickstart tutorial:

Account 3
  • Address: 0xf17f52151EbEF6C7334FAD080c5704D77216b732
  • Private key: 0xae6ae8e5ccbfb04590405997ee2d52d2b330726137b875053c36d94e974d162f
  • Initial balance: 0x90000000000000000000000 (2785365088392105618523029504 in decimal)

Start a node not on the nodes allowlist​

In your Permissioned-Network directory, create a Node-5 directory and data directory inside it.

Change to the Node-5 directory and start Node-5 specifying the Node-1 enode URL as the bootnode:

besu --data-path=data --bootnodes="<EnodeNode1>" --genesis-file=../genesis.json --rpc-http-enabled --rpc-http-api=ADMIN,ETH,NET,PERM,IBFT --host-allowlist="*" --rpc-http-cors-origins="*" --p2p-port=30307 --rpc-http-port=8549

Start another terminal and use curl to call the JSON-RPC API net_peerCount method:

curl -X POST --data '{"jsonrpc":"2.0","method":"net_peerCount","params":[],"id":1}' localhost:8549

The result confirms Node-5 has no peers even though it specifies Node-1 as a bootnode:

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x0"
}

Stop nodes​

When finished using the permissioned network, stop all nodes using Ctrl+C in each terminal window.

tip

To restart the permissioned network in the future, start from step 7.