The bootstrap nodes were probably the first ones on the DHT: hence, no bootstrap needed. If it's a new bootstrap node, it's connected to the old bootstrap nodes, or some other set of nodes in the DHT, just like any other node: distributed, not federated.
But once a node is acutually inside the DHT, it should never need to talk to the bootstrap nodes ever again: that's a pretty major win, in some respects.
Sorry, that was supposed to be a silly joke, but it also made it horribly unclear. I meant: How do you find the nodes to bootstrap yourself into the DHT in the first place? They must be IPs shipped with the client?
