# aptitude update
# aptitude install samba

# adduser --system --no-create-home --ingroup nogroup --disabled-login smbguest

Verifions:

# id smbguest
uid=115(smbguest) gid=65534(nogroup) groupes=65534(nogroup)
# passwd -S smbguest
smbguest L 10/29/2007 0 99999 7 -1

Editer /etc/samba/smb.conf .

[global]
      workgroup = <NOM_DU_WORKGROUP>
      server string = %h server (Samba %v)
      map to guest = Bad User
      null passwords = Yes
      obey pam restrictions = Yes
      guest account = smbguest
      passwd program = /usr/bin/passwd %u
      passwd chat = *Enter\snew\sUNIX\spassword:* %n\n *Retype\snew\sUNIX\spassword:* %n\n .
      syslog = 0
      log file = /var/log/samba/log.%m
      max log size = 1000
      dns proxy = No
      ldap ssl = no
      panic action = /usr/share/samba/panic-action %d
      invalid users = root
      hosts allow = 192.168., 127.0

[homes]
      comment = Home Directories
      create mask = 0755
      browseable = No

[printers]
      comment = All Printers
      path = /tmp
      create mask = 0700
      printable = Yes
      browseable = No

[print$]
      comment = Printer Drivers
      path = /var/lib/samba/printers

[public]
      path = /home/thierry/smbshare/public
      guest only = Yes
      guest ok = Yes