samba - Aug 2006 - Disable anonymous domain logins?

I've tried several settings, cannot seem to disable domain logins using 
the "nobody" account.   Using samba-3.0.10-1.4E.6 with 
openldap-servers-2.2.13-4 and smbldap-tools-0.9.1-1.2.el4.rf on Centos 4.

Thanks,

-Jeff