CODEWITHSUNDEEP
ethereum
sjensen85
sjensen85

Reputation: 150

Connecting Ethereum nodes that are on different machines

I am experimenting with Ethereum. I have successfully setup a private testnet via the instructions on the site. However, I am having trouble adding peers from different machines. On any node I create, the admin.nodeInfo.NodeUrl parameter is undefined. I have gotten the enode address by calling admin.nodeInfo and when I try the admin.addPeer("enode://address") command (with the public IP,) it returns true but the peers are not listed when calling admin.peers.

I read on another thread (here) that the private testnet is only local, but I am seeing plenty of documentation that suggests otherwise (here and here.) I have tried the second tutorial adding the command-line flags for custom networkid and genesis block.

Any advice would be much appreciated. Please let me know if I can provide more details.

Upvotes: 3

Views: 3213

Answers (1)

Raymond Carl
Raymond Carl

Reputation: 368

It is difficult to find in the available documentation but a key function is admin.addPeer().

https://github.com/ethereum/go-ethereum/wiki/JavaScript-Console

There are a few ways you could do it I suppose, but I have 1 node running on my local PC and one node running on a remote server. This saves me Ether while testing contracts and keeps me from polluting the Ethereum blockchain with junk. The key when running the admin.addPeer() is to find the "enode" for each of the notes such that you will run the function to look something like this on one of the nodes: admin.addPeer(enode@ipaddress:port). If you run admin.peers and see something other than an empty list, you were probably successful. The main thing to check for is that the enode ID and ip address from admin.peers match what you were expecting.

The geth configuration settings are a little tricky as well. You will have to adopt it for your particular uses, but here are some of the parameters I use:

geth --port XYZ --networkid XYZ --maxpeers X

Replace XYZ and X with the numbers you want to use and make sure you run the same parameters when starting both notes. There could be more parameters involved, but that should get you pretty far.

Disclaimer: I'm new to Geth myself as well as using computers for anything more than facebook, so take my answer with a grain of salt. Also, I haven't given you my full command line with starting up Geth because I'm not 100% sure on whether some of the parameters are related to a private testnet and which are not. I've only given you the ones that I'm sure are related to running a private testnet.

Also, you may find that can't execute any transactions which running a private test net. That's because you need one of them to start mining. So run: miner.start(X) when you are ready to start deploying contracts.

I apologize for this not being fully complete, but just passing on my experience after spending 1-2 weeks trying to figure out myself because the documentation isn't full clear on how to do this. I think it should be actively discouraged in the spirit of Ethereuem, but in my case, I run primarily not to pollute the blockchain.

PS. As I was just getting ready to hit submit, I found this that also sheds more light.

connecting to the network

Upvotes: 3

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