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.
See Provisioning Bitcoin Network Crawler
Copyright (c) 2014 Addy Yeow Chin Heng <ayeowch@gmail.com>
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