This testvar must be explicitly defined in the configuration file
This parameter specifies the IPv6 address for the CDRouter IPv6 gateway on the WAN. This testvar is normally used for DHCPv6 relay configurations and is not normally defined. CDRouter uses this address as its IPv6 gateway on the WAN. If not specified, CDRouter uses the testvar ipv6WanIspAssignIp as the gateway. For more information please see this Application Note: /kb/articles/show/257.