Under (yet) undetermined contidions nmbd doesn't appear to be able to register itselt as domain master browser. Apparently there is a problem with the UNICAST_SUBNET address which is wrongly assumed. In the logs, with log level > 4 it reports something like UNICAST_SUBNET server UNKNOWN (and either the lo address or the eth0 address as broadcast address) I've seen postings of this problem from as far as 2001 and since version 1.9.x. The most common error users report is that a machine (usually WinNT,2k or XP) cannot join the domain stating that 'A domain controler for the domain cannot be contacted (...) error 0x0000232b'. Equally, when this problem appears the server is unable to resolve addresses other than its own thru WINS, though wins.dat correctly registers all addresses. The workgroup is invisible when browsing from any other workstation, and, reaching the shares through \\servername show a 'Unknown' named node where de workgroup name should be. Can not yet tell how to replicate the problem.
The problem was fixed, and it was not a samba bug, but, guess what... It was another fantastic 'undocumented feature' from MS(TM). I happened to stumble with the cause of this behaviour. At least for the environment I was working with, the Windows machines, when having dhcp client enabled, are unable to contact correctly with the WINS server or the PDC through NetBIOS. Everything works fine if you give them fixed IP/DNS ip/WINS ip and disable -> 15 sec pause -> enable the network connection. There is a minor issue with SAMBA tough, which should be documented by itself, possibly in a BUG report by itself: The problem I reported in the end of the bug description <QUOTE> The workgroup is invisible when browsing from any other workstation, and, reaching the shares through \\servername show a 'Unknown' named node where the workgroup name should be. </END QUOTE> disappeared when I removed the line '127.0.0.1 localhost' from the lmhosts file.