Check that nmbd is running:
ps -eaf | grep nmbd
Result:
root 3422 1 0 10:30 ? 00:00:00 /usr/sbin/nmbd -D root 5178 4327 0 11:14 pts/0 00:00:00 grep --color=auto nmbd
If nmbd does not appear in the list reported by ps, it should be started as root using the normal means (/usr/local/samba/bin/nmbd -D).
Samba servers have a special NetBIOS name, __SAMBA__, to which they will always respond. By querying the server for this name, we can verify that nmbd is working correctly. The -U flag is used to specify the address to which the query should be sent.
nmblookup -U 127.0.0.1 __SAMBA__
Result:
querying __SAMBA__ on 127.0.0.1 192.168.0.2 __SAMBA__<00> 192.168.1.2 __SAMBA__<00>
If nmbd is not running, the following error message will be shown:
name_query failed to find name __SAMBA__
This can also be caused by not including the loopback interface name for the interfaces parameter in smb.conf and setting bind interfaces only = yes