i need to understand the difference between Main Network and Private Network.
Private network is only for test or it can be used for a real project?
Thank you
so it depends, if you want to use the public ethereum blockchain (accessible by anybody) the main network is where you deploy production applications. a private network means you create one or many ethereum nodes and only and people you give permission to have access to those nodes, you could use that for testing for example or in a company setting where you have private data. there are other public networks that are for testing only such as Ropsten, Rinkeby and Kovan
It seems to me that there is a fundamental issue when using a private Ethereum network for anything else than test and experimentation:
Depending on the number of nodes you intend to deploy, you will have to reduce the complexity of the POW consensus significantly. It means that the security and integrity of your private blockchain will not rely anymore on the blockchain itself but on external protections to prevent fraudulent nodes to join your network. Then why use Ethereum at all ?
Mainnet
Private network