When configuring a Samba server, remember that the discovery of machines on the network happens not only with DNS but also with a few other mechanisms too. I recently setup a number of virtual machines for developers, that were created by cloning a single instance. Mistakenly, I thought that adding a DNS config entry for each virtual machine on the host's /etc/hosts would be enough, but it's not. What we found was that everyone was connecting to the same VM (another requirement was that they be on the same subnet).