Is it possible to estimate the amount of nodes (hosts) are connected to the Bitcoin network in a given time?
Note: Here node means host.
Bitcoin Stack Exchange is a question and answer site for Bitcoin crypto-currency enthusiasts. It only takes a minute to sign up.Sign up to join this community
Not very accurately, because it depends on what you consider a node. A host is even more unclear.
Websites such as bitnodes.io provide a number of listening nodes, but that doesn't necessarily guarantee that they are operating as such, or doing any transaction verification:
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 messages 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:0.8.x/), so nodes running an 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.