I created a private ethereuem network using geth, and now I want other machine to join my network, I try this command :
geth --datadir node1/ --syncmode 'full' --port 30304 --rpc --rpcaddr 'localhost' --rpcport 8504 --rpcapi 'personal,db,eth,net,web3,txpool,miner' --bootnodes 'enode://20c47b4a7bd6d8383f87c1c988e601c7aa27ba7177b25d57e00794d1917c0c992dc37b93dfdf54741633179fd9a96a34fc2687d606ad48e2015ef2d958f3f0fb@10.2.1.124:30310' --networkid 1515 -unlock '0x6747efc15a7209763e840c8bbf381b721aeababd' --password node1/password.txt
But it doesn't sync with others nodes, and when I copy the genesis.json from connected machine and run:
geth --datadir node1/ init genesis.json
than I repeated the first command line it works!
so I want to know why I must have the genesis.json of a network to join it?