Beginning with Symantec Data Loss Prevention 14.0, IPv6 traffic is supported by Data Loss Prevention Network Prevent for Web.
Traffic from client devices with IPv6 addresses can be monitored by Data Loss Prevention Network Prevent for Web 14.0 and later. If a policy is violated and an incident is created, the incident detail will show IPv6 information.
Note: The ICAP connnection between the Network Prevent for Web Server and the proxy server still needs to be on an IPv4 network.