Windows 7 / Networking

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IPv6 Support

To solve problems with limited public IPv4 addresses, many governments, Internet service providers (ISPs), and other organizations are transitioning to IPv6, the next version of the Network layer protocol that drives the Internet. Windows Vista and Windows 7 support the following enhancements to IPv6 when compared to Windows XP:

• Dual IP layer stack enabled by default Windows Vista and Windows 7 support a dual IP layer architecture in which the IPv4 and IPv6 implementations share common transport (including TCP and UDP) and framing layers, as Figure below illustrates. Windows Vista and Windows 7 both enable IPv4 and IPv6 by default. You don't need to install a separate feature to obtain IPv6 support. You can disable either IPv4 or IPv6 for a network adapter, however.
  
  
  
  
• Graphical user interface-based configuration In Windows Vista and Windows 7, you can now configure IPv6 settings manually through a set of dialog boxes in the Network Connections folder (similar to the way you manually configure IPv4 settings). In addition, you can configure both IPv4 and IPv6 using the Netsh command.
• Integrated IPsec support In Windows Vista and Windows 7, IPsec support for IPv6 traffic is the same as that for IPv4, including support for Internet Key Exchange (IKE) and data encryption. The Windows Firewall with Advanced Security and IP Security Policies snap-ins now support the configuration of IPsec policies for IPv6 traffic in the same way as for IPv4 traffic. For example, when you configure an IP filter as part of an IP filter list in the IP Security Policies snap-in, you can now specify IPv6 addresses and address prefixes when specifying a specific source or destination IP address.
• MLDv2 Multicast Listener Discovery version 2 (MLDv2), specified in RFC 3810, provides support for source-specific multicast traffic. MLDv2 is equivalent to Internet Group Management Protocol version 3 (IGMPv3) for IPv4.
• LLMNR Link-Local Multicast Name Resolution (LLMNR) allows IPv6 hosts on a single subnet without a DNS server to resolve each other's names. This capability is useful for single-subnet home networks and ad hoc wireless networks.
• IPv6 over PPP The built-in remote access client now supports IPv6 over the Pointto- Point Protocol (PPP) (PPPv6), as defined in RFC 2472. Native IPv6 traffic can now be sent over PPP-based connections. For example, PPPv6 support allows you to connect with an IPv6-based ISP through dial-up or PPP over Ethernet (PPPoE)-based connections that might be used for broadband Internet access.
• Random interface IDs for IPv6 addresses To prevent address scans of IPv6 addresses based on the known company IDs of network adapter manufacturers, Windows Vista, Windows 7, and Windows Server 2008 by default generate random interface IDs for non-temporary, autoconfigured IPv6 addresses, including public and link-local addresses.
• DHCPv6 support Windows Vista, Windows 7, and Windows Server 2008 include a DHCPv6-capable DHCP client that will perform stateful address autoconfiguration with a DHCPv6 server. Windows Server 2008 includes a DHCPv6-capable DHCP Server service.