Samba4 AD config

readme.txt

First,

apt install samba winbind libnss-winbind libpam-winbind

before changing any configs.

Then, stop them.
systemctl stop smbd nmbd winbind

Clear the cache dirs of any previous state: *.ldb , *.tdb
smbd -b | egrep "LOCKDIR|STATEDIR|CACHEDIR|PRIVATE_DIR"

add 'winbind' to the end of 'passwd:' and 'group:' in nsswitch.conf

Import the configuration files given, changing USERS.SLLABS.COM for your chosen subdomain. Don't use your root.tld.

Join the domain.

net ads join -U administrator

start winbind.
systemctl start winbind
start nmbd and smbd.
systemctl start nmbd smbd

testing:
wbinfo -u
should list domain users.
wbinfo -g
should list domain groups.
getent passwd Administrator
should return a login account with a unix UID and GID in the 30ks, not blank.

getent group "domain admins"
should return a list of users with a gid.

handle XATTR based acls:

apt install acl

setfacl -m g:"domain admins":rwx /srv/it
setfacl -m g:"domain users":rx /srv/it

This was cribbed from
http://monklinux.blogspot.com/2017/09/how-to-samba-4-file-server-as-member.html
But that targeted debian9.

krb5.conf

[libdefaults]
	default_realm = USERS.SLLABS.COM

# The following krb5.conf variables are only for MIT Kerberos.
	kdc_timesync = 1
	ccache_type = 4
	forwardable = true
	proxiable = true

# The following encryption type specification will be used by MIT Kerberos
# if uncommented.  In general, the defaults in the MIT Kerberos code are
# correct and overriding these specifications only serves to disable new
# encryption types as they are added, creating interoperability problems.
#
# The only time when you might need to uncomment these lines and change
# the enctypes is if you have local software that will break on ticket
# caches containing ticket encryption types it doesn't know about (such as
# old versions of Sun Java).

#	default_tgs_enctypes = des3-hmac-sha1
#	default_tkt_enctypes = des3-hmac-sha1
#	permitted_enctypes = des3-hmac-sha1

# The following libdefaults parameters are only for Heimdal Kerberos.
	fcc-mit-ticketflags = true

[realms]
	USERS.SLLABS.COM = {
		kdc = dc00
		admin_server = dc00
	}

[domain_realm]
	.users.sllabs.com = USERS.SLLABS.COM
	users.sllabs.com = USERS.SLLABS.COM
	.sllabs.com = USERS.SLLABS.COM
	sllabs.com = USERS.SLLABS.COM

[appdefaults]
	pam = {
	  debug = false
	  ticket_lifetime = 36000
	  renew_lifetime = 36000
	  forwardable = true
	  krb4_convert = false
	}

smb.conf

#
# Sample configuration file for the Samba suite for Debian GNU/Linux.
#
#
# This is the main Samba configuration file. You should read the
# smb.conf(5) manual page in order to understand the options listed
# here. Samba has a huge number of configurable options most of which 
# are not shown in this example
#
# Some options that are often worth tuning have been included as
# commented-out examples in this file.
#  - When such options are commented with ";", the proposed setting
#    differs from the default Samba behaviour
#  - When commented with "#", the proposed setting is the default
#    behaviour of Samba but the option is considered important
#    enough to be mentioned here
#
# NOTE: Whenever you modify this file you should run the command
# "testparm" to check that you have not made any basic syntactic 
# errors. 

#======================= Global Settings =======================

[global]

## Browsing/Identification ###

# Change this to the workgroup/NT-domain name your Samba server will part of
	workgroup = SLLABS

# server string is the equivalent of the NT Description field
	server string = %h server (Samba4, Ubuntu)

# Windows Internet Name Serving Support Section:
# WINS Support - Tells the NMBD component of Samba to enable its WINS Server
#   wins support = no

# WINS Server - Tells the NMBD components of Samba to be a WINS Client
# Note: Samba can be either a WINS Server, or a WINS Client, but NOT both
;   wins server = w.x.y.z

# This will prevent nmbd to search for NetBIOS names through DNS.
	dns proxy = no

#### Networking ####

# The specific set of interfaces / networks to bind to
# This can be either the interface name or an IP address/netmask;
# interface names are normally preferred
;   interfaces = 127.0.0.0/8 eth0

# Only bind to the named interfaces and/or networks; you must use the
# 'interfaces' option above to use this.
# It is recommended that you enable this feature if your Samba machine is
# not protected by a firewall or is a firewall itself.  However, this
# option cannot handle dynamic or non-broadcast interfaces correctly.
;   bind interfaces only = yes



#### Debugging/Accounting ####

# This tells Samba to use a separate log file for each machine
# that connects
	log file = /var/log/samba/log.%m
	log level = 3

# Cap the size of the individual log files (in KiB).
	max log size = 1000

# If you want Samba to only log through syslog then set the following
# parameter to 'yes'.
#   syslog only = no

# We want Samba to log a minimum amount of information to syslog. Everything
# should go to /var/log/samba/log.{smbd,nmbd} instead. If you want to log
# through syslog you should set the following parameter to something higher.
	syslog = 2

# Do something sensible when Samba crashes: mail the admin a backtrace
	panic action = /usr/share/samba/panic-action %d


####### Authentication #######

# Server role. Defines in which mode Samba will operate. Possible
# values are "standalone server", "member server", "classic primary
# domain controller", "classic backup domain controller", "active
# directory domain controller". 
#
# Most people will want "standalone sever" or "member server".
# Running as "active directory domain controller" will require first
# running "samba-tool domain provision" to wipe databases and create a
# new domain.
;	server role = standalone server

# If you are using encrypted passwords, Samba will need to know what
# password database type you are using.  
;	passdb backend = tdbsam

;	obey pam restrictions = yes

# This boolean parameter controls whether Samba attempts to sync the Unix
# password with the SMB password when the encrypted SMB password in the
# passdb is changed.
;	unix password sync = yes

# For Unix password sync to work on a Debian GNU/Linux system, the following
# parameters must be set (thanks to Ian Kahan <<[email protected]> for
# sending the correct chat script for the passwd program in Debian Sarge).
;	passwd program = /usr/bin/passwd %u
;	passwd chat = *Enter\snew\s*\spassword:* %n\n *Retype\snew\s*\spassword:* %n\n *password\supdated\ssuccessfully* .

# This boolean controls whether PAM will be used for password changes
# when requested by an SMB client instead of the program listed in
# 'passwd program'. The default is 'no'.
;	pam password change = yes

# This option controls how unsuccessful authentication attempts are mapped
# to anonymous connections
	map to guest = bad user

########## Domains ###########

#
# The following settings only takes effect if 'server role = primary
# classic domain controller', 'server role = backup domain controller'
# or 'domain logons' is set 
#

# It specifies the location of the user's
# profile directory from the client point of view) The following
# required a [profiles] share to be setup on the samba server (see
# below)
;   logon path = \\%N\profiles\%U
# Another common choice is storing the profile in the user's home directory
# (this is Samba's default)
#   logon path = \\%N\%U\profile

# The following setting only takes effect if 'domain logons' is set
# It specifies the location of a user's home directory (from the client
# point of view)
;   logon drive = H:
#   logon home = \\%N\%U

# The following setting only takes effect if 'domain logons' is set
# It specifies the script to run during logon. The script must be stored
# in the [netlogon] share
# NOTE: Must be store in 'DOS' file format convention
;   logon script = logon.cmd

# This allows Unix users to be created on the domain controller via the SAMR
# RPC pipe.  The example command creates a user account with a disabled Unix
# password; please adapt to your needs
; add user script = /usr/sbin/adduser --quiet --disabled-password --gecos "" %u

# This allows machine accounts to be created on the domain controller via the 
# SAMR RPC pipe.  
# The following assumes a "machines" group exists on the system
; add machine script  = /usr/sbin/useradd -g machines -c "%u machine account" -d /var/lib/samba -s /bin/false %u

# This allows Unix groups to be created on the domain controller via the SAMR
# RPC pipe.  
; add group script = /usr/sbin/addgroup --force-badname %g

############ Misc ############

# Using the following line enables you to customise your configuration
# on a per machine basis. The %m gets replaced with the netbios name
# of the machine that is connecting
;   include = /home/samba/etc/smb.conf.%m

# Some defaults for winbind (make sure you're not using the ranges
# for something else.)
;   idmap uid = 10000-20000
;   idmap gid = 10000-20000
;   template shell = /bin/bash

# Setup usershare options to enable non-root users to share folders
# with the net usershare command.

# Maximum number of usershare. 0 (default) means that usershare is disabled.
;	usershare max shares = 100

# Allow users who've been granted usershare privileges to create
# public shares, not just authenticated ones
;	usershare allow guests = yes
;	username map = /etc/samba/smbusers
;	security = user
;	encrypt passwords = yes
;	guest ok = yes
;	guest account = localadmin

############ LOCAL ############
	server role = member server
	security = ads
	realm = USERS.SLLABS.COM
	dedicated keytab file = /etc/krb5.keytab
	kerberos method = secrets and keytab
	idmap config * : backend = tdb
	idmap config * : range = 10000-20000
	idmap config USERS : backend = rid
	idmap config USERS : range = 30000-40000
	encrypt passwords = yes
	winbind refresh tickets = yes
	winbind offline logon = yes
	winbind enum users = yes
	winbind enum groups = yes
	winbind nested groups = yes
	winbind expand groups = 2
	winbind use default domain = yes
	os level = 20
	domain master = no
	local master = no
	preferred master = no
	host msdfs = no
	netbios name = adminfs
	client min protocol = SMB2
	client max protocol = SMB3
	hosts allow = 10.0.0.0/21
	unix extensions = no
	reset on zero vc = yes
	veto files = /.bash_logout/.bash_profile/.bash_history/.bashrc/
	hide unreadable = yes
	acl group control = yes
	acl map full control = true
	ea support = yes
	vfs objects = acl_xattr
	store dos attributes = yes
	dos filemode = yes
	dos filetimes = yes
	restrict anonymous = 2
	strict allocate = yes
	load printers = no
	printing = bsd
	printcap name = /dev/null
	disable spoolss = yes
	username map = /etc/samba/user.map

#======================= Share Definitions =======================

# Un-comment the following (and tweak the other settings below to suit)
# to enable the default home directory shares. This will share each
# user's home directory as \\server\username
;[homes]
;   comment = Home Directories
;   browseable = no

# By default, the home directories are exported read-only. Change the
# next parameter to 'no' if you want to be able to write to them.
;   read only = yes

# File creation mask is set to 0700 for security reasons. If you want to
# create files with group=rw permissions, set next parameter to 0775.
;   create mask = 0700

# Directory creation mask is set to 0700 for security reasons. If you want to
# create dirs. with group=rw permissions, set next parameter to 0775.
;   directory mask = 0700

# By default, \\server\username shares can be connected to by anyone
# with access to the samba server.
# Un-comment the following parameter to make sure that only "username"
# can connect to \\server\username
# This might need tweaking when using external authentication schemes
;   valid users = %S

# Un-comment the following and create the netlogon directory for Domain Logons
# (you need to configure Samba to act as a domain controller too.)
;[netlogon]
;   comment = Network Logon Service
;   path = /home/samba/netlogon
;   guest ok = yes
;   read only = yes

# Un-comment the following and create the profiles directory to store
# users profiles (see the "logon path" option above)
# (you need to configure Samba to act as a domain controller too.)
# The path below should be writable by all users so that their
# profile directory may be created the first time they log on
;[profiles]
;   comment = Users profiles
;   path = /home/samba/profiles
;   guest ok = no
;   browseable = no
;   create mask = 0600
;   directory mask = 0700

;[printers]
;	comment = All Printers
;	browseable = no
;	path = /var/spool/samba
;	printable = yes
;	guest ok = no
;	read only = yes
;	create mask = 0700

# Windows clients look for this share name as a source of downloadable
# printer drivers
;[print$]
;	comment = Printer Drivers
;	path = /var/lib/samba/printers
;	browseable = yes
;	read only = yes
;	guest ok = no
# Uncomment to allow remote administration of Windows print drivers.
# You may need to replace 'lpadmin' with the name of the group your
# admin users are members of.
# Please note that you also need to set appropriate Unix permissions
# to the drivers directory for these users to have write rights in it
;   write list = root, @lpadmin

[it]
	comment = IT and Software Share
	path = /srv/it
	writeable = yes
	browseable = yes
	guest ok = yes
	create mask = 0770
	valid users = @"Domain Admins" @"Domain Users"
	write list = @"Domain Admins" @"Domain Users"

user.map

!root = USERS\Administrator USERS\administrator Administrator administrator

Here is a pretty picture.