Best way to check you're connected to the real main net?

Question

If you're running an application which connects to a node to send and validate transactions, what is the best way to check the node is connected to the real Ethereum main net? I'm thinking of the scenario where the user of the application intentionally feeds the node a fake version of Ethereum so they can modify the state to suit there purposes or fake making the transactions to the real main net chain.

Answer 1

There are 2 ways of doing it that I know.

1. Check the latest block number against whats there in ethstats.net
2. If you do any txn check for it on etherscan.io

Answer 2

you can try : version.getnework :

web3.version.getNetwork((err, netId) => {
  switch (netId) {
    case "1":
      console.log('This is mainnet')
      break
    case "2":
      console.log('This is the deprecated Morden test network.')
      break
    case "3":
      console.log('This is the ropsten test network.')
      break
    case "4":
      console.log('This is the Rinkeby network.')
      break;
    case "42":
      console.log('This is the Kovan network.')
    default:
      console.log('This is an unknown network.')
  }
})