[Samba] Please review my smb.conf

[DavidA]

Hi

I'm please to report that all my Windows machines can now see the Samba 
Share on my Raspberry Pi.  I never got network discovery to work properly 
but, by specify the Pi's name in the Windows Hosts file and by mapping a 
Windows drive to the share, the Windows machines can now access the share. 
Thanks very much Rowland and others who helped me.

My share is currently open to anyone who is connected to my network, which 
is not ideal.  I would like to add some security.  Below are the main 
sections of my smb.conf file, please will you advise me what to do to add 
secure access?

Should I create a 'guest' user account on the Pi and require external users 
to use that account?

Best regards

David

[global]
    usershare allow guests = yes
    workgroup = WORKGROUP
    wins support = true
    map to guest = bad user
    dns proxy = no
    passwd program = /usr/bin/passwd %u
    panic action = /usr/share/samba/panic-action %d
    max log size = 1000
    os level = 20
    passwd chat = *Enter\snew\s*\spassword:* %n\n 
*Retype\snew\s*\spassword:* %n\n *password\supdated\ssuccessfully* .
    log file = /var/log/samba/log.%m
    passdb backend = tdbsam
    pam password change = yes
    server role = standalone server
    obey pam restrictions = yes
    syslog = 0
    unix password sync = yes
    netbios name = RPHS
    name resolve order = wins lmhosts hosts bcast

[homes]
   comment = Home Directories
   browseable = no

   read only = yes
   create mask = 0700
   directory mask = 0700
   valid users = %S

[Data]
    comment=Raspberry Pi Share
    path = /mnt/data
    browseable=yes
    writeable = yes
    only guest = no
    public = yes