Current Network Status

Bitcoins day to day functionality depends on the peer to peer network. This is just a collection of bitcoin clients running on various machines across the internet.

Total Number of Bitcoin Clients

There are currently as of September 2011 approximately 60,000] active clients. We know this because as part of the protocol every client broadcasts their address across the internet every 24 hours. By listening for these broadcasts and counting the number of unique addresses we can count the number of clients.

Number of Listening Bitcoin Clients

One of the issues that the peer to peer network faces is the issue that most users of the internet use machines that are behind a Firewall/NAT gateway. This means that they are only able to make outgoing connections to hosts on the internet and not receive incoming connections. There are over 12,000 bitcoin clients that can be connected to. This figure could be an underestimate of the actual number of hosts that are not behind a firewall as each host is configured to only accept 125 connections, and so if they are full we would not know if the host was behind a firewall or just ignoring out connection request.

Ratio of Listening to Total Number of Hosts

All hosts are configured to make 8 outgoing connections. With this and the fact that there is a limit of 125 total connection once the ratio of total hosts to listening hosts approaches 15 there will be issues with hosts connecting to the network. As of September 2011 this ratio is between 4 and 5 so is not an issue.