sentences:  If a query arrives with a search string that matches one of the files in the leaves, the ultrapeer replies and pointing to the specific leaf.In version 0.4 of the Gnutella protocol, an ultrapeer which receives a message from a leaf node (message with hop count zero) knows for sure that the message was originated from that leaf node.In version 0.6 of the protocol, If an ultrapeer receives a message from an ultrapeer with hop count zero then it knows that the message originated by the ultrapeer or by one of its leaves (The average number of the leaves nodes that are connected to an ultrapeer is 200).