MSDN Documentation

Introduction to IPv6

IPv6 addresses the limitations of IPv4 by providing a vastly larger address space and introducing new features to enhance network performance, security, and manageability. Key advantages include:

• 320-bit Address Space: Extends the address space significantly, allowing for an almost unlimited number of unique IP addresses.
• Simplified Header Format: Reduces overhead for routers, leading to more efficient packet processing.
• Improved Support for Security: Built-in support for IPsec (Internet Protocol Security) is mandatory, enhancing end-to-end security.
• Autoconfiguration: Stateless address autoconfiguration (SLAAC) simplifies network setup.
• Better Support for Mobility and QoS: Enhanced features for mobile devices and quality of service.

IPv6 Addressing in Windows

Windows supports a variety of IPv6 address types:

• Unicast Addresses: Identifies a single network interface.
  • Global Unicast Addresses: Routable on the global internet.
  • Link-Local Addresses: Used for communication on a local network segment (link).
  • Unique Local Addresses (ULAs): Similar to private IPv4 addresses, used for local networks.
• Multicast Addresses: Used to send a packet to a group of interfaces.
• Anycast Addresses: Identifies a set of interfaces, where a packet is delivered to the nearest interface in the set.

An example of a global unicast IPv6 address:

2001:0db8:85a3:0000:0000:8a2e:0370:7334

This can often be represented more concisely by omitting leading zeros and compressing consecutive zero-filled blocks:

2001:db8:85a3::8a2e:370:7334

IPv6 Configuration and Management

Windows provides several tools and methods for configuring and managing IPv6 on your network:

• Network and Sharing Center: Graphical interface for basic network settings.
• PowerShell: Advanced command-line tools for comprehensive configuration.
• Netsh command-line utility: A powerful tool for network configuration.

To view IPv6 configuration for an interface using PowerShell:

Get-NetIPAddress -InterfaceAlias "Ethernet" -AddressFamily IPv6

To enable IPv6 on an adapter (if disabled):

Enable-NetAdapterBinding -Name "Ethernet" -ComponentID ms_tcpip6

Transition Mechanisms

As the internet transitions from IPv4 to IPv6, several transition mechanisms are employed to ensure interoperability:

• Dual Stack: A host or router supports both IPv4 and IPv6 simultaneously.
• Tunneling: Encapsulating IPv6 packets within IPv4 packets for transport over IPv4 networks (e.g., 6to4, Teredo).
• Translation: Mechanisms like NAT64 and DNS64 allow IPv6-only hosts to communicate with IPv4-only servers.

Key IPv6 Features in Windows

• Native IPv6 Support: Built into the Windows operating system since Windows Vista and Windows Server 2008.
• IPsec Integration: Robust security features for network communication.
• Router Advertisements (RA): Used for stateless autoconfiguration.
• Neighbor Discovery Protocol (NDP): Replaces ARP in IPv4, used for address resolution and router discovery.