You can use Unified Access Gateway to act as a bridge for IPv6 Horizon clients to connect to an IPv4 back end Connection Server or agent environment.

You can deploy Unified Access Gateway in twonic mode with the front-end NIC in mixed IPv4/IPv6 mode and the Horizon back end or management NIC in IPv4 mode. The Horizon back end environment might consist of Connection Servers, agent desktops, or other server-side infrastructure.

Note: When you configure Unified Access Gateway in IPv4/IPv6 mode, ensure that the Blast External URL for TCP/UDP is set to 443. See Deployment with Horizon and Horizon Cloud with On-Premises Infrastructure and Configure Horizon Settings.
The following Horizon client and server IP modes are supported.
Table 1. Supported Horizon Settings (IP Modes)
Horizon Client Mode Horizon Server Mode Supported
IPv4 IPv4 Yes
IPv6 IPv4 Yes
IPv6 IPv6 Yes
IPv4 IPv6 No

When installing a Horizon client, if you select Automatic Selection or Dual, connection occurs over IPv4 or IPv6, depending on the current network.