Unit 3: User management and Kerberos authentication¶
This unit introduces the
ipa CLI program and the web
interface. We will perform some simple administrative tasks: adding
groups and users and managing group membership.
https://server.ipademo.local/. You’ll get a TLS
untrusted issuer warning which you can dismiss (by adding a temporary
exception). Log in as
Welcome to the FreeIPA Web UI. Most management activities can be
performed here, or via the
ipa CLI program. Use the Web UI to
perform the following actions:
Add a User with the username
Add a User Group for system administrators named
Make sure you have a Kerberos ticket for
Most FreeIPA administrative actions can be carried out using the
ipa CLI program. Let’s see what commands are available:
[server]% ipa help commands automember-add Add an automember rule. automember-add-condition Add conditions to an automember rule. automember-default-group-remove Remove default (fallback) group for all unmatched entries. automember-default-group-set Set default (fallback) group for all unmatched entries. automember-default-group-show Display information about the default (fallback) automember groups. ...
Whoa! There are nearly 400 commands! We’ll be using only a handful
of these today. Note that command completion is enabled in the
shell, so you can type a partial command and press
couple of times to see what commands are available, e.g. all the
commands starting with
[server]$ ipa cert-<TAB> cert-find cert-request cert-show cert-remove-hold cert-revoke cert-status
You’ll notice that commands are grouped by topic, or the kind of
object they act upon. Run
ipa help topics to list all topics.
You can read a general overview of a topic by running
<topic>, and specific information on a particular command by
ipa help <command>.
Add a user named
bob from the CLI. Use the CLI help to find the
right command (hint: the
user plugin provides the command).
We have seen how to authenticate as
admin. The process is the
same for regular users - just
Try to authenticate as
[server]$ kinit bob kinit: Pre-authentication failed: Invalid argument while getting initial credentials
If you did not encounter this error, congratulations - you must be
a disciplined reader of documentation! To set an initial password
when creating a user via the
ipa user-add command you must
--password flag (the command will prompt for the
ipa passwd command to (re)set a user’s password:
[server]$ ipa passwd bob New Password: Enter New Password again to verify: ---------------------------------------- Changed password for "bob@IPADEMO.LOCAL" ----------------------------------------
Whenever a user has their password reset (including the first time
it is set), the next
kinit will prompt them to enter a new
[server]$ kinit bob Password for bob@IPADEMO.LOCAL: Password expired. You must change it now. Enter new password: Enter it again:
bob has a TGT (run
klist to confirm) which he can use to
authenticate himself to other hosts and services. Try logging into
[server]$ ssh firstname.lastname@example.org Creating home directory for bob. [bob@client]$
You are now logged into the client as
exit to log out and return to the
server shell. If you run
klist again, you will see not only the TGT but a service ticket
that was automatically acquired to log in to
client.ipademo.local without prompting for a password. Kerberos
is a true single sign-on protocol!
[server]$ klist Ticket cache: KEYRING:persistent:1000:1000 Default principal: bob@IPADEMO.LOCAL Valid starting Expires Service principal 06/04/2018 21:45:50 06/05/2018 21:38:24 host/client.ipademo.local@IPADEMO.LOCAL 06/04/2018 21:38:41 06/05/2018 21:38:24 krbtgt/IPADEMO.LOCAL@IPADEMO.LOCAL
Now that you have created some users, it’s time to define some access policies. Proceed to Unit 4: Host-based access control (HBAC).
Alternatively, if you are interested in SSH public key management for users and hosts, jump ahead to Unit 10: SSH user and host key management.