A VCN can either be created and IPv6 enabled upon time of creation or it can be manually enabled and setup. The following prerequisites are required before you can enable IPv6 on your VM. 

1) Ensure IPv6 is enabled on your VCN. This can be done by entering your VCN settings, selecting the CIDR blocks menu and then selecting “Add IPv6 CIDR block” if there is no IPv6 block there.  If there is no previous IPv6 block a message should asking you to “Confirm Enable IPv6”. Simply click “Confirm”.

2) Next, create a subnet and enable IPv6 if there is no subnet in the “Subnet” menu. If there is already an existing subnet simply edit the existing subnet and enable IPv6 on it.

3) Ensure that you have an existing Internet Gateway or create an Internet Gateway in the “Internet Gateways” menu.

4) Add a route or modify your default route in the “Route Tables” menu so that the subnet can know how to access the internet. To do so, you must add an IPv6 route rule, the target type will be “Internet Gateway”, the “Destination CIDR Block” will be “::/0” and the “Target Internet Gateway” will be the gateway we previously created. 

4) The second to last step is to add an “Egress Rule” under the “Security List Details”. The “Destination CIDR” is “::/0” and the “IP Protocol” is “All Protocols”. 

5) The final step is to assign the IPv6 address to the VM. To do so, go to the “Instance Details” of the instance, then “Attached VNICs” and select the VNIC. From there, go to “IPv6 Addresses” and select “Assign IPv6 Address” and assign an address to it. Putty into the instance now and then if necessary use the “sudo dhclient -6 ens3” to force the OS to pull the IPv6 address assigned to the VM. You should now be able to ping google.com using IPv6.