The VMware USB Redirection panel is divided in two sections: the Options section (highlighted in red in the image below) and the Rules section (highlighted in blue in the image below).
In the Options section, two groups of options define the global behavior of VMware USB Redirection and Device Splitting.
In the lower Rules section, you can find the USB Device Redirection rules and Auto Device Splitting rules, which specify the redirection actions for particular devices or device classes.
¶ Option Section
Two options are available on this section: Device redirection and Auto device splitting.
Effectiveness of Device Redirection and Auto Device Splitting Options
After modifying the Device Redirection or Auto device splitting settings, restart the endpoint device to ensure the changes take effect.
¶ Device Redirection
This option defines the USB redirection behavior.
The Device Redirection option establishes the default fallback action (allow/deny) of the Redirection Rules. If the USB device connected to the endpoint does not match any of the rules define in the redirection-rule list, the fallback option(allow/deny) defined in the Option Section is applied.
Possible default fallback actions:
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Allow: Devices not explicitly denied will be allowed for USB redirection (more open behaviour). To block specific devices, you must define a rule for each device you want to deny.
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Deny: Devices not explicitly allowed will be denied for USB redirection (more restrictive behaviour). To enable specific devices, you must define a rule for each device you want to allow.
Implications of the Device Redirection Option Fallback Action
Consider the implications of setting the Device Redirection option fallback action to either Allow or Deny.
Allow: If the fallback action is set to Deny, any device not listed in the rules will not be redirected. This provides greater reliability but reduces control.
Deny: If the fallback action is set to Deny, any device not listed in the rules will not be redirected. This offers more control but may reduce reliability.
VMware Device Redirection Option default
By default, the Device Redirection Option is set to Allow.
¶ Auto Device Splitting
This option determines whether USB composite devices can be split into separate interfaces.
The Auto Device Splitting option defines the default fallback action (allow/deny/undefined) for the Split Device Rules. If a USB device connected to the endpoint does not match any of the rules defined in the Split Device Rules list, the fallback option(allow/deny/undefined) specifiedin the Options section will be applied.
Possible default fallback actions:
- Allow: All composite devices not explicitly denied will automatically be split into their separate interfaces. A rule is required for each device that should remain joined.
- Deny: All composite devices not explicitly allowed will remain joined. A rule is required for each device that should be split into its separate interfaces.
- Undefined: For composite devices not explicitly allowed or denied by a specific rule, the splitting action will prompt the user for a decision. A rule is required for devices that should consistently ask the user about their split status.
Auto device splitting vs. Device redirection
Auto Device Splitting options only define the operation mode for a composite device.However, allowing or denying USB device redirection is determined solely by the redirection rules and the fallback redirection option.
¶ Rules Section
The VMware USB Redirection, offers two different kinds of rules:
- Device redirection rules.
- Device split rules.
These lists are placed in the lower section of the VMware USB Redirection Tab.
The Rules section is partitioned in Redirection rules list (highlighted in blue in the previous image) and in Split Devices rules list (highlighted in red in the previous image).
The Redirection Rules list is placed over the Split Devices Rules list: slide the scroll bar down in order to display the Split Device Rules list.
VMware Predefined USB Redirection rules
The VMware client does not include any predefined USB redirection or Split Devices rules. Both USB Redirect and Split Devices Rules lists are empty.
Any new USB redirection or Split Devices rule will be always inserted at the bottom of the related list.
Each type of rule (redirection/split) can be defined either as Allow or as Deny. The action(allow/deny) of rule is distinguished by an icon at the left of the description:
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The Allow rules are characterised by a green circle with a white check mark.
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The Deny rules are characterised by a red circle with a white cross.
VMware USB redirection rules position
For both type of rules, USB Redirection and Split Devices rules, the position in the list is meaningless since only one rule can be configured for each USB device.
¶ USB Redirection Rule
A USB Redirection rule consists of parameters which are specified in order to define it:
- Redirection Rule Actions
- Parameters characterising the object of a rule.
¶ Redirection Rule Actions
Set the rule action either to Allow or Deny.
VMware Default Redirection Rule Action
Be aware: The default value for the rule action is Allow
¶ Parameters characterising the object of a Redirection Rule
Parameters characterising the object of a USB redirection rule are:
- VID (Vendor ID).
- PID (Product ID).
- VMware class.
Use the scroll bar to access all parameters. For more details about VID and PID parameters, read USB device ID and USB class.
Class term meaning in VMware implementation
The meaning of Class is defined by USB-IF (USB Implementers Forum) (see https://www.usb.org) and the can be found at https://www.usb.org/defined-class-codes.VMware use a proprietary definition of the term Class in USB redirection. Classes are identified by a text label, not by a number.
The VMware USB device classes list is published at: https://docs.vmware.com/en/VMware-Horizon-7/7.5/horizon-remote-desktop-features/GUID-890C33DC-6E3B-4E01-8A6F-6E3AE4DB0390.html.
With VMware USB redirection rule definitions, a device can be identified in two mutually exclusive ways (i.e., selecting VID and PID disables the VMware class field and vice versa):
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Using VID and PID: in this case, both VID and PID must be specified. It is not possible to use only VID or only PID as the device identifier. A USB Redirection rule uniquely defines a specific device by its VID and PID. If you attempt to create a rule for a device that already has an existing VID and PID, a message will appearat the left bottom of the NEW USB redirection rule window, as shown in the picture below.
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Using a VMware Class: while it is possible to define multiple USB Redirection rules for a specific VMware Class, it is not recommended.
¶ Split Device Rule
A VMware USB Split device rule defines whether a USB composite device should be split into its different interfaces or not.
A split device rule consists of parameters that define its behavior:
- Actions
- Parameters that characterize the object of the rule
¶ Split Rule Actions
Set the rule action to either Allow or Deny.
VMware Default Splitting Rule Action
Be aware: The default value for the rule action is Allow.
¶ Parameters characterising the object of a split device rule
The parameters characterising the object of a USB redirection rule are:
- VID (Vendor ID).
- PID (Product ID).
It is possible to define split device rules for specific USB devices. Both VID and PID must be specified; you cannot use only VID or only PID as the device identifier.
It is not possible to define a split device rule for VMware classes.
When trying to establish a rule to an already in used VID and PID device, a message appears at the left bottom of the NEW USB redirection rule window indicating: device already in list .
¶ How to create a USB Redirection or a Split Device Rule for a specific device connected to the endpoint
In order to create a new rule, click on ADD REDIRECTION RULE or ADD SPLIT RULE button.
Opening the USB redirection rule or Split device rule configuration windows displays all configurable rule parameters.
Set the rule action by choosing either Allow or Deny.
For more details about rule action refer to the Redirect Rule Actions and Split Rule Actions paragraph.
Default rule action
Be aware: The default value for the Redirection/Split Rule action is Allow.
Open the Available devices drop-down list of connected devices by clicking on the downward arrow on the right.
The connected devices list appears.
Scroll through the list and select the device. Note that the keyboard and mouse are also included on the list.
Selecting a device will automatically populate the Description, VID and PID fields with the corresponding values from the device list.
If the Description field is modified and associated with a device from the Available devices list, the customized description will take priority over the default system device name.
Rule description
The Description field in the rule is displayed in the rule list. Using a meaningful name allows for easy identification of each rule.When an item is selected from the Available devices list, the description field is automatically filled with the system's USB device name, which may not always be very descriptive.
To modify it, select the Description field and enter a more relevant label. The Description field is a mandatory parameter.
For more details about rule object parameters refer to Parameters characterising the object of a redirection rule and Parameters characterising the object of a split device rule.
Press OK to save the new rule.
Required Parameters & OK Button
If all the required parameters to create a rule have not been defined, the OK button remains disabled.
¶ How to create a USB Redirection or a Split Device Rule for devices not connected to the endpoint
To create a USB redirection/Split device rule for a device not connected to the endpoint or for a VMware class that cannot use the Available devices list, click on the ADD REDIRECTION RULE or ADD SPLIT RULE button at the top of the rules section in the VMware USB Redirection tab.
Opening the USB redirection rule or Split device rule configuration windows displays all configurable rule parameters.
Set the rule action, choosing either Allow and Deny.
For more details about rule action, refer to Redirect Rule Actions and Split Rule Actions.
Default rule action Be aware: The default value for the rule action is Allow.
Type in the Description field the text that will identify the rule in the rules list; this is a mandatory parameter.
Rule description The rule Description field will display the information shown in the rule list. Choose a meaningful description to help identify each rule.
For the USB Redirection rule, the rule object is identified either by VID and PID, or by a group of devices using VMware Classes.
For the Split Device rule, the object is identified solely by PID and VID.
For more details about rule object parameters refer to the link Parameters characterising the object of a redirection rule and Parameters characterising the object of a split device rule.
Press OK to save the new rule.
Required Parameters & OK Button
If all the required parameters to create a rule have not been defined, the OK button remains disabled.
¶ Modify and Delete USB Redirection or Split Device Rules
Once a Device Redirection/Split Device rule has been created, it cannot be modified.
To delete a rule, hover the mouse pointer over the right side of the rule until a red trash icon appears, then click on it. The rule will be deleted immediately, without a confirmation prompt.
