If a Samba server is a member of a Windows NT Domain (see the security = domain parameter) then periodically a running smbd process will try and change the MACHINE ACCOUNT PASSWORD stored in the TDB called private/secrets.tdb . This parameter specifies how often this password will be changed, in seconds. The default is one week (expressed in seconds), the same as a Windows NT Domain member server. See also smbpasswd 8, and the security = domain parameter. 604800