Message Security Mode for Horizon Components

You can set the message security mode to specify the security mechanism used when JMS messages pass among VMware Horizon components.

The following table shows the options you can select to configure the message security mode. To set an option, select it from the Message security mode list on the Security Settings tab on the Global Settings page.

Table 1. Message Security Mode Options

Option	Description
Disabled	Message security mode is disabled.
Mixed	Message security mode is enabled but not enforced. You can use this mode to detect older components in your VMware Horizon environment. The log files generated by Connection Server contain references to these components. This setting is not recommended. Use this setting only to discover components that need to be upgraded.
Enabled	Message security mode is enabled, using a combination of message signing and encryption. JMS messages are rejected if the signature is missing or invalid, or if a message was modified after it was signed. Some JMS messages are encrypted because they carry sensitive information such as user credentials. If you use the Enabled setting, you can also use IPSec to encrypt all JMS messages between Connection Server instances, and between Connection Server instances and Unified Access Gateway appliances.
Enhanced	SSL is used for all JMS connections. JMS access control is also enabled so that desktops and Connection Server instances can only send and receive JMS messages on certain topics.

When you first install VMware Horizon on a system, the message security mode is set to Enhanced. If you upgrade VMware Horizon from a previous release, the message security mode remains unchanged from its existing setting.

Important: If you plan to change an upgraded VMware Horizon environment from Enabled to Enhanced, you must first upgrade all Connection Server instances and VMware Horizon desktops. After you change the setting to Enhanced, the new setting takes place in stages.

1. You must manually restart the VMware Horizon Message Bus Component service on all Connection Server hosts in the pod, or restart the Connection Server instances.
2. After the services are restarted, the Connection Server instances reconfigure the message security mode on all desktops, changing the mode to Enhanced.
3. To monitor the progress in Horizon Console, go to Settings > Global Settings.

   On the Security Settings tab, the Enhanced Security Status item will show Enhanced when all components have made the transition to Enhanced mode.

   Alternatively, you can use the vdmutil command-line utility to monitor progress. See Using the vdmutil Utility to Configure JMS Message Security Mode.

If you plan to change an active VMware Horizon environment from Disabled to Enabled, or from Enabled to Disabled, change to Mixed mode for a short time before you make the final change. For example, if your current mode is Disabled, change to Mixed mode for one day, then change to Enabled. In Mixed mode, signatures are attached to messages but not verified, which allows the change of message mode to propagate through the environment.