The Amazon EC2 Instance Metadata Service, Amazon Time Sync Service, and Amazon VPC DNS server can now be accessed over IPv6 endpoints by instances built on the Nitro System . These local instance services have IPv6 addresses that can be accessed from your Amazon EC2 instances. These IPv6 endpoints use Unique Local Addresses (ULA); IPv6 for local instance services is useful for running software and containers in an IPv6-only single stack configuration. Additionally, if you are starting your transition to IPv6 in a dual-stack environment, the endpoints for the Instance Metadata Service, Amazon Time Sync Service, and Amazon VPC DNS are available over both IPv4 and IPv6.