Recently I've setup a private chain on cloud (to be more accurate, it is a separate public chain), after a few days, I found that there are some strange transactions sending ether to the same account every second. I've re-setup the instance several times, but it keeps occur.

Is it under attack? How can I secure the chain? Would it related to the RPC setting?

2 Answers 2


If you have to provide rpc api to the public then keep mining nodes and rpc nodes separate. Do not provide the rpc api from the miner. Connect RPC provider nodes to the miner as peers. No need to unlock the account in the rpc provider node. RPC provider node will provide rpcapi and relays transactions from client to miner. In this way client can never access miners directly but need to go through the rpc provider nodes and all the nodes will operate safely.

  • Can I say that, when the account is unlock in the RPC provider node, client no need to sign on the transaction which cause this accident? In this setup, do I need put the miner node in private network, and make only the RPC node public? Is there any problem if I enable all RPC API?
    – Franky Lau
    Commented Jun 6, 2018 at 2:18
  • Also disable the ipc in all the nodes. Now you can make all the nodes public. Be aware of the APIs you need to provide.
    – biplavo
    Commented Jun 6, 2018 at 11:42

I guess it depends how you have set it up.

If the nodes are not accessible for others, then the transactions are obviously caused by your actions (or bugs in the code or something like that). If the nodes are accessible for others, is the chain minable? If not, nobody can succesfully make transactions as they don't have the necessary Ether to pay for the transactions.

If the chain's nodes are accessible and you can mine on it and someone has mined Ether for themselves to pay for the transactions.. Well, consider changing the settings.

Or maybe one of your nodes is mining and has set the mining rewards to be sent to one address which causes the transactions?

  • It is a standalone mining node, and the coinbase has 2000000000000000 ether at the begining. The port 30303 and rpc port 8545 is open to public. When the strange transactions start sending to my node, all ether gone within a second.
    – Franky Lau
    Commented Jun 5, 2018 at 10:20
  • I've several chain, some use POW, some use POA, but all the chain face the same issue.
    – Franky Lau
    Commented Jun 5, 2018 at 10:27

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