How big is the Ripple network? The size of the Bitcoin network is available here:

http://bitcoinstatus.rowit.co.uk/

As the page says, they do this by listening for Address messages that are broadcast over the network.

Since the Ripple server is now open-source, we can expect a number of individuals and companies to start running their own nodes. Is there a way to estimate the size of the network, either using an RPC command on the server, or by modifying the server code itself to collect some information about the peers?

I would be interested in the following numbers:


Number of public servers
Number of validators


I imagine the first one could be obtained by querying peers recursively. Unfortunately the RPC interface is only available to 127.0.0.1 by default. As for the second metric, I'm guessing we can get this by looking at the ledger.
I would estimate that there are 30 public servers and 11 validators as I'm typing this answer.

I estimated the number of public servers by connecting to a number of servers and collecting the node keys of every server connected to them. While node keys are free to change, each server has a unique node key while it is connected. This is used to drop duplicate connections. So this should count each public server once.

I estimated the number of validators by collecting the validator public keys of every validation I saw published over a five minute period. I counted the number of unique validation keys.

I can't see any reason these counts could be too high, but they certainly could be missing some.