Enabling Kerberos Access Control In order to enable Kerberos on your DECwindows system, you or your system administrator must have first: 1. Installed and configured the TCP/IP for OpenVMS Alpha software. 2. Installed and configured the Kerberos Client for OpenVMS software. 3. Enabled the SECURITY extension by adding the extension abbreviation (SEC_XAG) to the DECW$SERVER_ EXTENSIONS parameter in the SYS$MANAGER:DECW$PRIVATE_ SERVER_SETUP file. For example: $ DECW$SERVER_EXTENSIONS == "SEC_XAG,XINERAMA,DBE" 4. Obtained the following information: * Location of the KDC * The appropriate node, domain, and realm information for adding principals * Your principal name and password See the Kerberos Client for OpenVMS documentation for information on how to install the Kerberos Client software. Authorizing Access To grant a set of valid Kerberos principals access to your workstation display: 1. Choose Security... from Session Manager's Options menu. The Security Options dialog box is displayed. 2. Under Server Access Control, choose Kerberos. 3. Click on the Configure Principals button. 4. Enter the specification(s) for the Kerberos principal(s) you want to add to the Authorized Principals list. The format of a typical Kerberos principal is pri- mary/instance@REALM. 5. Click on the Add button. The principal is added to the Authorized Principals box. 6. Click on OK to save and apply the changes and close the Configure Principals dialog box. The Kerberos Login dialog box is displayed, and you are prompted to log in and verify your Kerberos credentials. 7. Enter your Kerberos principal name and password, and click OK. Disabling Access To disable Kerberos, deselect the Kerberos option, and click OK or Apply. To prevent one or more principals from accessing your session, first click on the name(s) you want to remove. Then click on the Remove button. Finally, click on OK or Apply. The principal will no longer have authorized access to your workstation. Revoking a Ticket Kerberos client credentials are cached for future reuse. If you believe one or more tickets have been compromised, you can flush the credentials cache by disabling Kerberos (both server and client options) and clicking on the Revoke Ticket button.