I have two ubuntu systems with ethereum installed. I started the node in each system using the following command : -

geth --datadir 'path of node folder' init 'path of genesis.json'
geth --datadir 'path of node folder' --networkid 12512 console

The systems are connected to a local network. The genesis file in both the systems are same. The time is in sync. But when I execute admin.addPeer("enode@ip:port"), I am getting net.peerCount as 0. There was no error while pinging the ip from one system to the other. Executing 'netstat -ntpl' gave the following:

machine 1: tcp6 0 0 :::30303 :::* LISTEN 3423/geth
machine 2: tcp6 0 0 :::30303 :::* LISTEN 3028/geth

Any help is appreciated.

  • 1
    Possible duplicate of Peer discovery not working on private network
    – niksmac
    Nov 25, 2016 at 16:04
  • add --nodiscover to geth nodes to stop default discovery.
    – Raj
    Nov 28, 2016 at 3:28
  • This is not a duplicate, since in the other question the solution was to manually add peers. In this question, the OP did not make this mistake, so the solution will necessarily be different. Nov 29, 2016 at 1:32

1 Answer 1


There were two things I needed to do:

1. Turn on UPnP in my network settings.

2. 'Genesis block mismatch'. Though I had the same genesis file in both the nodes I was getting this error. So I replaced it with the following:-

  "nonce": "0x0000000000000042",
  "timestamp": "0x0",
  "parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
  "extraData": "0x0",
  "gasLimit": "0x8000000",
  "difficulty": "0x400",
  "mixhash": "0x0000000000000000000000000000000000000000000000000000000000000000",
  "coinbase": "0x3333333333333333333333333333333333333333",
  "alloc": {

from https://souptacular.gitbooks.io/ethereum-tutorials-and-tips-by-hudson/content/private-chain.html"

This resolved the connectivity issue.

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