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I am trying to use an Ubuntu computer to set up Samba shares for a lab of Windows computers (Vista Basic and XP). Two of the shares need logins, but one is supposed to be a public share. My problem is that when a Windows computer attempts to login to a public share (without first logging into another share) it prompts for a username/password.

I know that this problem could be solved by setting "security = share" in the smb.conf file, but I have also read that doing so can cause other security problems and that "security = user" is ideally what should be used. I also know that the smb.conf manual states that "security = user" makes Windows authenticate before accessing a share.

So my main question is, is it possible to use "security = user" for a guest share without Windows prompting for login? Or does Samba not make exceptions for guest shares?

Here is my smb.conf file, for reference:


    workgroup = hsbclib
    server string = %h server (Samba, Ubuntu)
    dns proxy = no
    log file = /var/log/samba/log.%m
    max log size = 1000
    syslog = 0
    panic action = /usr/share/samba/panic-action %d
    obey pam restrictions = yes
    unix password sync = yes
    passwd program = /usr/bin/passwd %u
    passwd chat = *Enter\snew\s*\spassword:* %n\n *Retype\snew\s*\spassword:* %n\n *password\supdated\ssuccessfully* .
    pam password change = yes
    map to guest = bad user
    usershare allow guests = yes
    security = user
    guest ok = yes
    guest account = publicuser
    username map = /etc/samba/smbusers


    comment = All Printers
    browseable = no
    path = /var/spool/samba
    printable = yes
    create mask = 0700


    comment = Printer Drivers
    path = /var/lib/samba/printers


    path = /srv/smb/mabusclass
    writeable = yes
    valid users = mabus, mabusclass


    path = /srv/smb/yearbook
    writeable = yes
    valid users = yearbook


    comment = Free Public Storage
    path = /srv/smb/public
    writeable = yes
    guest ok = yes
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1 Answer 1

From http://blog.realcomputerguy.com/2010/12/samba-and-guest-shares-with-security.html?spref=tw

In a nutshell you need:

  • A username map file.
  • A valid 'nix "guest" user mapped to the Windows guest account ("nobody" in most distros).
  • Proper smb.conf configuration.

In this example our username map file is /etc/samba/smbusers. It maps a 'nix user to a Windows user.

In /etc/samba/smbusers (many distros include this file, but with the default commented out):

nobody = guest

In /etc/samba/smb.conf:

   security = user
   Map to guest = Bad User
   username map = /etc/samba/smbusers
-- no 'valid users =' line --

   guest ok = yes
-- no 'valid users =' line --
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If the remote computer still asks for password, try checking the samba logs for more info. On a server i had the user nobody returning NT_STATUS_LOGON_FAILURE and ntlm_password_check: NO NT password stored for user nobody, that point me that samba already had a user nobody configured. pdbedit nobody returned a user, confirming that samba was trying to use it instead of the "guest" role for nobody. the fix was removing it from samba: pdbedit -x nobody and everything worked fine –  higuita Oct 16 '13 at 18:22

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