Tuesday, February 9, 2010

Connecting RHEL to Active Directory Server through Winbind

You have a RHEL system and you want to authenticate it against your active directory. The good news is that Red Hat has made it easy for you to do this. The bad news is that they only get the most basic structure working for you.

Here I will show you how to get WinBind authentication working using Authconfig, and how make it a little more seamless than this utility leaves it off.

It should be noted that while this works perfectly well, it is really not the best way to authenticate users against a UNIX host. Given the option, having your users in OpenLDAP and PAM authenticating them against that would be a much better option. However, we don’t live in a perfect world, and sometimes we just have to make things work.

Let’s start by using authconfig to join your machine to the domain. This should all be done as the root user.

# authconfig

* Select “Use Winbind” and Use “Winbind Authentication”. Remember to leave “Cache Information”, “Use MD5 Passwords” and “Use Shadow Passwords” selected.
* Select “Next”
* Under “Security Model” select “ads”
* “Domains:” examplead (substatute with the name of your Active Directory)
* “Domain Controllers:” adserver.domain.com (Again, substitute with the name of your Active Directory server)
* “Template Shell:” /bin/bash
* Select “Join Domain”
* Select “OK”

Now your machine should be be on the domain. Test it to make sure you can see your AD users:

# wbinfo -u

You should see your users in the list.

The only problem is that to do anything with them, you have to express their user name in that annoying way Windows likes you to. Something like this:


Not very usefull. To get around this, simply edit “/etc/samba/smb.conf” and change this line:

winbind use default domain = no

to this:

winbind use default domain = yes

You should now be able to express AD usernames without the domain nonsense before it. Try it:

# finger username
Login: username Name: Username
Directory: /home/EXAMPLEAD/username Shell: /bin/bash
Never logged in.
No mail.
No Plan.

Finally check your “/etc/nsswhich.conf” file to make sure RHEL knows to use WinBind. Authconfig should have set this up for you, and it should have lines that look like this:

passwd: files winbind
shadow: files winbind
group: files winbind

Note:Follow these instructions to have your users directories automatically created….


1 comment:

  1. Do you have a way to reverse this whole process? Is there an authconfig command to revert all changes and go back to the default settings so as to remove a RHEL system from an Active Directory domain?