Using Active Directory for Ubuntu

This information is deprecated. It should be considered end of life and should not be used in any production setting

Step 1: Install the Required Packages

Note: Enter Y when asked if you want to install the additional packages

apt-get install krb5-user
apt-get install winbind samba

Step 2: Edit the /etc/krb5.conf File

[logging]
default = FILE10000:/var/log/krb5lib.log
[libdefaults]
ticket_lifetime = 24000
default_realm = DOMAIN.INTERNAL
default_tkt_enctypes = des3-hmac-sha1 des-cbc-crc
default_tgs_enctypes = des3-hmac-sha1 des-cbc-crc
[realms]
DOMAIN.INTERNAL = {
kdc = domainserver.domain.internal
admin_server = domainserver.domain.internal
default_domain = DOMAIN.INTERNAL
}
[domain_realm]
.domain.internal = DOMAIN.INTERNAL
domain.internal = DOMAIN.INTERNAL

Step 3: Edit /etc/samba/smb/conf

Notes: Change the NETBIOS name parameter to be correct for the server. Make a backup copy of the original file!!!

1) Make the edits. The configuration shown is the bare minimum and doesn't share anything.

[global]
security = ads
netbios name = CMHRG02
realm = DOMAIN.INTERNAL
password server = domainserver.domain.internal
workgroup = DOMAIN
idmap uid = 500-10000000
idmap gid = 500-10000000
winbind separator = +
winbind enum users = no
winbind enum groups = no
winbind use default domain = yes
template homedir = /home/%D/%U
template shell = /bin/bash
client use spnego = yes
domain master = no

2) Test the configuration with the testparm command

Step 4: Edit /etc/nsswitch.conf to look like the example below

passwd: compat winbind
group: compat winbind
shadow: compat
hosts: files dns wins
networks: files
protocols: db files
services: db files
ethers: db files
rpc: db files
netgroup: nis

Step 5: Modify the PAM settings

1) /etc/pam.d/common-account should contain only the following lines

account sufficient pam_winbind.so
account required pam_unix.so

2) /etc/pam.d/common-auth should contain only the following lines

auth sufficient pam_winbind.so
auth required pam_unix.so nullok_secure use_first_pass

3) Modify the /etc/pam.d/common-password file, so the max parameter is set to 50, similar to the one shown below

password required pam_unix.so nullok obscure min=4 max=50 md5

4) Make sure the /etc/pam.d/common-session file contains the following line

session required pam_mkhomedir.so umask=0022 skel=/etc/skel

Step 6: Make a directory to hold domain user home directories

Note: Use the value you put in the WORKGROUP tag of the /etc/samba/smb.conf file

mkdir /home/DOMAIN

Step 7: Initialize Kerberos

1) kinit domain_admin_account@DOMAIN.INTERNAL

Next check to be sure you got a ticket from the domain controller

2) klist

Step 8: Join the system to the Active Directory

net ads join -U domainadminuser@DOMAIN.INTERNAL

Step 9: Restart Samba-related Services (Or reboot the server

Note: The order is important

/etc/init.d/samba stop
/etc/init.d/winbind stop
/etc/init.d/samba start
/etc/init.d/winbind start

Step 10: Restart SSH and Test Connectivity

Note: If you rebooted the server in the previous step, just try and login.

/etc/init.d/ssh restart

ssh useraccount@server

If you can login using your active directory username and password then everything is working!

Step 11: Configure SUDO

1) First create a group in Active Directory called UnixAdmins and add the names of people whom you want to be able to use sudo to admin the server.

2) Next, add the UnixAdmins group to the /etc/sudoers so these users can use sudo

%UnixAdmins ALL=(ALL) ALL

HELPFUL COMMAND LINES

1) List the derived UNIX GID values for Active Directory groups

for gid in $(wbinfo -r <username>); \
do SID=$(wbinfo -G $gid);GROUP=$(wbinfo -s $SID); echo $gid is $GROUP; done

2) See the Active Directory SID for a particular named user

wbinfo –n <username>