Check_ntlm_password: Authentication for user ['name'] - ['name'] FAILED with error NT_STATUS_LOGON_FAILURE

Question

Hi,
We are running a Mountain Lion Server with Open Directory / LDAPv3, as far as I can tell.  My responsibility is to get my CentOS 6.3 box running Samba v. 3.5.10-125.el6 to authenticate users against the ML / OD box.  I can ssh to the CentOS box OK and I can get Guest access to the Samba share to go OK too.  Also, the OD passwords on the LDAP server are set to 'Open Directory' so I guess that means that they are encrypted and the Samba server is set to send encrypted passwords.  But when a user tries to properly authenticate using either say via a Mac client Finder [Command-K], or smbclient, the Samba server will generate this message:
check_ntlm_password:  Authentication for user ['name'] -> ['name'] FAILED with error NT_STATUS_LOGON_FAILURE
(I am blanking out the user name on purpose).
Of course there is more to the story, but those are the basics.
Here are the relevant parts of my smb.conf.  FWIW, the CentOS / Samba box is called Jupiter.
Thank you,
NickZ
[smb.conf]
[global]
          display charset = UTF-8
          realm = SATURN.MCLEAN.HARVARD.EDU
          netbios aliases = ANL
          server string = Welcome To The Jupiter Samba Server Version 3.5.10-125.el6
          interfaces = lo, em1
          security = SERVER
          update encrypted = Yes
          password server = saturn.mclean.harvard.edu
          smb passwd file = /var/lib/samba/private/secrets.tdb
          passdb backend = ldapsam:ldap://saturn.mclean.harvard.edu
          passwd program = /usr/bin/passwd %u
          unix password sync = Yes
          lanman auth = Yes
          client NTLMv2 auth = Yes
          client use spnego principal = Yes
          kerberos method = system keytab
          log level = 2
          syslog = 3
          log file = /var/log/samba/log.%m
          max log size = 50
          name resolve order = host lmhosts wins bcast
          server signing = auto
          preferred master = Auto
          ldap admin dn = uid=DirAdmin,cn=users,dc=saturn,dc=mclean,dc=harvard,dc=edu
          ldap group suffix = cn=groups
          ldap passwd sync = yes
          ldap suffix = dc=saturn,dc=mclean,dc=harvard,dc=edu
          ldap ssl = no
          ldap user suffix = cn=users
          usershare allow guests = Yes
          idmap backend = ldap:ldap://saturn.mclean.harvard.edu
          idmap uid = 10000-20000
          idmap gid = 30000-40000
          cups options = raw
[homes]
          comment = Home Directories
          read only = No
[printers]
          comment = All Printers
          path = /var/spool/samba
          printable = Yes
          browseable = No
[anl]
          comment = Main ANL Share
          path = /anl
          read only = No
          guest ok = Yes
          hide dot files = No

Answer 1

Turns out a printer driver installed on an XP (even W2K(?)) was (apparently?) flooding the OS X SMB server to the point of collapse. Uninstalling the "HP Tools" part of the driver cleared it up. The printer is an HP LJ1300. I had downloaded the full driver from HP.com. I don't know if any/all these conditions need to be matched, but: the printer was on the network using an HP print server JetDirect EX Plus, and the computer(s) in question were connecting directly to it (not via a print server). It's been too long ago, but there were always several errors in the System Log (Win XP Event Viewer) that correlated with the errors on the OS X server.
Proud to say that since that day (10+ months ago) I've not seen it happen again. whew.