Bitcoin network nodes are needed to ensure all valid Bitcoin transactions that ever occur are broadcasted to peers in the network in a timely manner. These nodes are currently made available by users on a voluntary basis with the aim to help secure the network from sybil attack. The charts from the Bitnodes project above provide a summary of the current state of these nodes. The Bitnodes Project was launched in April 2013 with Bitcoin Foundation’s help as a community resource.

As have been noted by many in the Bitcoin community, the number of the Bitcoin network nodes has been decreasing gradually over the past months. The mean reachable nodes now stands at 7,150. Almost 20% of these nodes are not directly contributing to the network as they continue to download a full copy of the blockchain from their peers, i.e. among the 80% of the synced nodes.

Furthermore, there are only 35% of the reachable nodes that are currently running the latest version of the Bitcoin reference client. This percentage represents not only the upgraded nodes but also new nodes that have only recently joined the network. We do, however, observe a healthy number of IPv6 nodes that makes up 5% of the network. As a comparison, out of the Alexa top 10,000 websites, approximately 3% of them are IPv6-enabled.

To this end, I would like to urge users familiar with provisioning web services on dedicated or virtual private servers to consider running one of the Bitcoin clients, e.g. Bitcoin Core. If you are already operating a Bitcoin network node, the Bitnodes Project now offers an alert tool to notify you when your node becomes unreachable by other peers in the network. To subscribe to alerts for your node, search for your node from https://getaddr.bitnodes.io/nodes/ and click on the link to your node status page.

The full list of updates made during 2014 Q3 from Jun 1, 2014 – Aug 31, 2014 is available at the address below:

https://github.com/ayeowch/bitnodes/wiki/Schedule#q3-june-1-2014—august-31-2014

About Bitnodes: Bitnodes is currently being developed to estimate the size of the Bitcoin network by finding all the reachable nodes in the network. The current methodology involves sending getaddr message recursively to find all the reachable nodes in the network starting from a set of seed nodes. Bitnodes uses Bitcoin protocol version 70001 (i.e. >= /Satoshi:0.7.x/), so nodes with older protocol version will be skipped. The crawler implementation in Python is available from *GitHub (ayeowch/bitnodes) and the crawler deployment is documented in Provisioning Bitcoin Network Crawler.*

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