I'm trying to get geth running on the testnet. I've successfully built it, but these commands never seem to work.

blockchain@ethereum:~/go-ethereum$ ./build/bin/geth --testnet --light console
INFO [08-25|22:58:28] Starting peer-to-peer node               instance=Geth/v1.7.0-unstable-3e0dbe0e/linux-amd64/go1.9
INFO [08-25|22:58:28] Allocated cache and file handles         database=/home/blockchain/.ethereum/testnet/geth/lightchaindata cache=128 handles=1024
INFO [08-25|22:58:28] Initialised chain configuration          config="{ChainID: 3 Homestead: 0 DAO: <nil> DAOSupport: true EIP150: 0 EIP155: 10 EIP158: 10 Metropolis: 9223372036854775807 Engine: ethash}"
INFO [08-25|22:58:28] Disk storage enabled for ethash caches   dir=/home/blockchain/.ethereum/testnet/geth/ethash count=3
INFO [08-25|22:58:28] Disk storage enabled for ethash DAGs     dir=/home/blockchain/.ethash                       count=2
INFO [08-25|22:58:28] Loaded most recent local header          number=0 hash=419410…ca4a2d td=1048576
INFO [08-25|22:58:28] Starting P2P networking 
WARN [08-25|22:58:28] Light client mode is an experimental feature 
INFO [08-25|22:58:28] RLPx listener up                         self="enode://569e2233c2908ba6a721bd682d5e34c99a4a033373628e649d4135daa041931886b0c23478933e87b7809de607f9672c6ecd8b1a301c7e3f6897a818254e8bd6@[::]:30303?discport=0"
INFO [08-25|22:58:28] IPC endpoint opened: /home/blockchain/.ethereum/testnet/geth.ipc 
Welcome to the Geth JavaScript console!

instance: Geth/v1.7.0-unstable-3e0dbe0e/linux-amd64/go1.9
 modules: admin:1.0 debug:1.0 eth:1.0 net:1.0 personal:1.0 rpc:1.0 txpool:1.0 web3:1.0

> eth.coinbase
Error: not supported
    at web3.js:3104:20
    at web3.js:6191:15
    at get (web3.js:6091:38)
    at <unknown>

> eth.blockNumber

I've waited over ten minutes; shouldn't I see coinbase and blockNumber updated when I am synced? Isn't --light supposed to make a "light sync" so I don't need to download the entire chain?

1 Answer 1


eht.coinbase is not supported because a light node is supposed to be used to broadcast TX and check BC values, not to do mining.

About block number, it seems your client cannot find any node to sync with. Try:


If it shows a void array [] it means you aren't in contact with any node so this is why your client is not syncing.

Try --syncmode light instead:

blockchain@ethereum:~/go-ethereum$ ./build/bin/geth --testnet --syncmode light console

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