Active directory authentication for Ubuntu Linux login and cifs mounting home directories...

Posted by Jamie on Server Fault See other posts from Server Fault or by Jamie
Published on 2010-04-23T23:48:23Z Indexed on 2010/04/23 23:54 UTC
Read the original article Hit count: 492

Filed under:

ubuntu

|

active-directory

|

pam

|

samba

|

cifs

I've configured my Ubuntu 10.04 Server LTS Beta 2 residing on a windows network to authenticate logins using active directory, then mount a windows share to serve as there home directory.

Here is what I did starting from the initial installation of Ubuntu.

Download and install Ubuntu Server 10.04 LTS Beta 2
Get updates

# sudo apt-get update && sudo apt-get upgrade
Install an SSH server (sshd)

# sudo apt-get install openssh-server

Some would argue that you should "lock sshd down" by disabling root logins. I figure if your smart enough to hack an ssh session for a root password, you're probably not going to be thwarted by the addition of PermitRootLogin no in the /etc/ssh/sshd_config file. If your paranoid or not simply not convinced then edit the file or give the following a spin:

# (grep PermitRootLogin /etc/ssh/sshd_conifg && sudo sed -ri 's/PermitRootLogin ).+/\1no/' /etc/ssh/sshd_conifg) || echo "PermitRootLogin not found. Add it manually."
Install required packages

# sudo apt-get install winbind samba smbfs smbclient ntp krb5-user
Do some basic networking housecleaning in preparation for the specific package configurations to come.
1. Determine your windows domain name, DNS server name, and IP address for the active directory server (for samba). For conveniance I set environment variables for the windows domain and DNS server. For me it was (my AD IP address was 192.168.20.11):
  
  # WINDOMAIN=mydomain.local && WINDNS=srv1.$WINDOMAIN
  
  If you want to figure out what your domain and DNS server is (I was contractor and didn't know the network) check out this helpful reference.
2. The authentication and file sharing processes for the Windows and Linux boxes need to have their clocks agree. Do this with an NTP service, and on the server version of Ubuntu the NTP service comes installed and preconfigured. The network I was joining had the DNS server serving up the NTP service too.
  
  # sudo sed -ri "s/^(server[ \t]).+/\1$WINDNS/" /etc/ntp.conf
  
  Restart the NTP daemon
  
  # sudo /etc/init.d/ntp restart
3. We need to christen the Linux box on the new network, this is done by editing the host file (replace the DNS of with the FQDN of the windows DNS):
  
  # sudo sed -ri "s/^(127\.0\.0\.1[ \t]).*/\1$(hostname).$WINDOMAIN localhost $(hostname)/" /etc/hosts
Kerberos configuration. The instructions that follow here aren't to be taken literally: the values for MYDOMAIN.LOCAL and srv1.mydomain.local need to be replaced with what's appropriate for your network when you edit the files.
1. Edit the (previously installed above) /etc/krb5.conf file.
  1. Find the [libdefaults] section and change (or add) the key value pair (and it is in UPPERCASE WHERE IT NEEDS TO BE):
    
    [libdefaults]
    default_realm = MYDOMAIN.LOCAL
    1. Add the following to the [realms] section of the file:
    MYDOMAIN.LOCAL = {
    kdc = srv1.mydomain.local
    admin_server = srv1.mydomain.local
    default_domain = MYDOMAIN.LOCAL
    }
    1. Add the following to the [domain_realm] section of the file:
    .mydomain.local = MYDOMAIN.LOCAL
    mydomain.local = MYDOMAIN.LOCAL
2. Conmfigure samba. When it's all said done, I don't know where SAMBA fits in ... I used cifs to mount the windows shares ... regardless, my system works and this is how I did it.
  1. Replace /etc/samba/smb.conf (remember I was working from a clean distro of Ubuntu, so I wasn't worried about breaking anything):
    
    [global]
    security = ads
    realm = MYDOMAIN.LOCAL
    password server = 192.168.20.11
    workgroup = MYDOMAIN
    idmap uid = 10000-20000
    idmap gid = 10000-20000
    winbind enum users = yes
    winbind enum groups = yes
    template homedir = /home/%D/%U
    template shell = /bin/bash
    client use spnego = yes
    client ntlmv2 auth = yes
    encrypt passwords = yes
    winbind use default domain = yes
    restrict anonymous = 2
  2. Start and stop various services.
    
    # sudo /etc/init.d/winbind stop
    # sudo service smbd restart
    # sudo /etc/init.d/winbind start
3. Setup the authentication.
  1. Edit the /etc/nsswitch.conf. Here are the contents of mine:
    
    passwd: compat winbind
    group: compat winbind
    shadow: compat winbind
    hosts: files dns
    networks: files
    protocols: db files
    services: db files
    ethers: db files
    rpc: db files
  2. Start and stop various services.
    
    # sudo /etc/init.d/winbind stop
    # sudo service smbd restart
    # sudo /etc/init.d/winbind start

At this point I could login, home directories didn't exist, but I could login. Later I'll come back and add how I got the cifs automounting to work.

Numerous resources were considered so I could figure this out. Here is a short list (a number of these links point to mine own questions on the topic):

Developer IT