Why enable Kerberos on your system?

Convenience and security. With Kerberos, a single login grants access to all NetBSD web services. Configuration is easy and you only have to do it once (sometimes less).

NetBSD

NetBSD needs to be configured to prevent Kerberos from being used to log into your system, and then to enable Kerberos.

  1. Either disable Kerberos auth for sshd, login, etc. in /etc/pam.d, or tell your relevant services not to use PAM.

    /!\ Disabling KerberosAuthentication in /etc/ssh/sshd_config does NOT prevent sshd from invoking pam_krb5.so and prompting for a Kerberos password -- oops. Since you probably do not have a host key in the realm NETBSD.ORG you have little to fear from ssh's KerberosAuthentication method -- nothing can get tickets to use your machine, because there is no host instance for your machine shared between the NetBSD kerberos server and your local keytab. So, the bottom line: turn off UsePAM for sshd or adjust your PAM configuration; don't worry about KerberosAuthentication or GSSAPIAuthentication in sshd itself.

  2. Create /etc/krb5.conf containing only the line [libdefaults].

NetBSD will now autodiscover and uses the NETBSD.ORG KDC as defined in DNS. To use Kerberized TNF services, log in with your Kerberos password:

$ kinit <username>@NETBSD.ORG

The right-hand side is a Kerberos realm, not a DNS domain. Case is significant!

Mac OS X

OS X autodiscovers and uses the NETBSD.ORG KDC as defined in DNS. To use Kerberized TNF services, log in with your Kerberos password:

  1. Launch Ticket Viewer.app from /System/Library/CoreServices

  2. Press the "Add Identity" button

  3. In the identity field enter your <username>@NETBSD.ORG

    The right-hand side is a Kerberos realm, not a DNS domain. Case is significant!

  4. Enter the password associated with this identity in the password field

    By default Ticket Viewer.app will save password details in keychain, un-tick "Remember password in my keychain" if this is not desired behaviour

  5. Press continue

If successful, you'll be returned to the main window with a new entry below the icons containing <username>@NETBSD.ORG and the date and time which the ticket obtained is due to expire.

Windows XP

Windows does not provide an easy way to configure and use KDCs different from the one embedded into an Active Directory.

Therefore, to use Kerberos, you should follow the following steps:

  1. Download the MIT Kerberos for Windows installer. It is composed of different tools traditionally found with Kerberos distributions, like kinit(1) or klist(1) , and a Network Identity Manager, an application used to manage credential caching of Kerberos tickets.

  2. Install the package. Use the default provided options, then restart the computer.

  3. The Network Identity Manager (PDF) should automatically start when you login. As there is no principal currently configured, it should open a dialog box to obtain the new credentials.

  4. Enter your principal:

    Username: Realm: NETBSD.ORG

  5. Click Ok. After a few seconds, it should obtain the TGT for you from the NETBSD.ORG KDC.

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