Red Hat Training

A Red Hat training course is available for Red Hat Enterprise Linux

3.2. Logging into IPA

Users are authenticated to IPA services, including the command-line tools and the web UI, using Kerberos authentication. This means that logging into Identity Management requires running kinit.
Running kinit issues the user a Kerberos ticket. This ticket is checked by any IPA or Kerberos-aware service, so that a user only needs to log in once to access all domain services. Domain services include the IPA web UI, mounted file shares, wikis, or any other application which uses IPA as its identity/authentication store.

3.2.1. Logging into IPA

Logging into Identity Management requires running kinit on a client within the IPA domain. 
$ kinit
The kinit command must be run from a machine which has been configured as a client within the IPA domain, so that the client retrieves authenticates with the IPA KDC.
Simply running kinit logs into IPA as the currently logged-in user account. This user account must also be an IPA user for them to authenticate to the IPA Kerberos domain successfully. For example, if you are logged into the machine as jsmith: 
$ kinit
Password for jsmith@EXAMPLE.COM:

Note

If SSSD or pam_krb5 is configured on the IPA client machine, then when a user logs into the machine, a ticket is created which can be used for machine services which require authentication, such as sudo.

3.2.2. Logging in When an IPA User Is Different Than the System User

To specify an IPA username — because a person's system username is different then the IPA username or to switch IPA user accounts — simply rerun the kinit command, specifying the new user. For example: 
$ kinit userName 
Password for userName@EXAMPLE.COM:
When the server was first set up, an administrative user, admin, is created to perform normal administrative activities. To authenticate as the admin user, use the name admin when running kinit: 
$ kinit admin

Note

Only one set of tickets can be stored per logged-in user. The current stored credentials are the ones that will be used when accessing IPA services.
If you were already connected to the IPA web UI as another user, refresh the browser to display the updated details for the new user.

3.2.3. Checking the Current Logged in User

Use the klist command to verify the identity and the ticket granting ticket (TGT) from the server: 
$ klist
Ticket cache: FILE:/tmp/krb5cc_500
Default principal: ipaUser@EXAMPLE.COM

Valid starting     Expires            Service principal
11/10/08 15:35:45  11/11/08 15:35:45  krbtgt/EXAMPLE.COM@EXAMPLE.COM

Kerberos 4 ticket cache: /tmp/tkt500
klist: You have no tickets cached
It's important to know who the authenticated user is because the currently-authenticated user is the only one who can access the IPA services. The Kerberos client libraries for kinit have some limitation, one of them being that the current ticket is overwritten with any new invocation of kinit. Authenticating as User A and then authenticating as User B overwrites User A's ticket.
To allow there to be multiple authenticated users on a machine, set the KRB5CCNAME environment variable. This variable keeps credential caches separate in different shells.

3.2.4. Caching User Kerberos Tickets

Only one set of tickets can be stored per logged-in user. The current stored credentials are the ones that will be used when accessing IPA services.
For example, if you authenticated as admin, added a new user, set the password, and then tried to authenticate as that user, the administrator's ticket is lost.
To keep separate credential caches in different shells, a special environment variable, KRB5CCNAME, can be used.