Then add some addresses you can find on this page. You could also have to update your nodes, while the core is not running (I've heard it could be), edit the gnutella2.ini and find the "redirectors" line. If you experience this problem, you can put G2-server_connection_timeout to 20 or 25. It seems that some users (I do) have problems connecting to Gnutella2 nodes while others don't.
Gnutella2 is very close to "releasable" state in MLdonkey. Protocol details can be found at the Gnutella2 Developer Network. (The conflict started because some gnutella developers argued that the "Gnutella2" name conveys an upgrade or superiority, which is why nowadays, it is mostly referred to as G2 to avoid this old conflict.) Mostly abbreviated as "G2" and sometimes also named "Mike's protocol" (or "MP) and not very well accepted by most of the Gnutella dev community, due to the historical naming conflict.
Supports Metadata, searching by hash and other important P2P features. OpenSource protocol designed based on the original Gnutella protocol, with extensability in mind and a better searching algorithm.