IPv6 traffic between nodes on different subnets of an IPv6 internetwork

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

IPv6 traffic between nodes on different subnets of an IPv6 internetwork

This configuration requires three computers (two hosts and one router) and additional router configuration beyond the installation of the IPv6 protocol. There are two separate network segments (also known as links or subnets) and an IPv6-capable router that forwards IPv6 packets between hosts on the segments.

The following illustration shows the configuration of two hosts on separate network segments that are connected by a router.

By default, the IPv6 protocol for the Windows Server 2003 family configures link-local IP addresses for each interface that correspond to installed Ethernet network adapters. Link-local addresses have the prefix of FE80::/64. The last 64 bits of the IPv6 address are the interface identifier, as derived from the 48-bit MAC address of the network adapter. For more information, see IPv6 interface identifiers. With link-local addresses, Host A and Host B can communicate with the router computer, but not with each other.

In this configuration, additional site-local prefixes are advertised by the router. The site-local prefixes are used by Host A and Host B to automatically configure site-local addresses that are derived from the 48-bit MAC address of the network adapter. After Host A and Host B have site-local addresses, they can communicate with each other.

To obtain the interface index numbers of the two Ethernet adapters on the router computer, type the following command for each adapter:

netsh interface ipv6 show interface [interface=]String

Where String is the name or index of the interface, (for example, Local Area Connection). Subnet 1 is the network segment to which Host A is attached. Subnet 2 is the network segment to which Host B is attached.

After you have obtained the interface index numbers, type the following commands on the router computer:

netsh interface ipv6 set interface [interface=]Subnet1InterfaceIndex [forwarding=]enabled [advertise=]enabled

netsh interface ipv6 set interface [interface=]Subnet2InterfaceIndex [forwarding=]enabled [advertise=]enabled

netsh interface ipv6 add route [prefix=]FEC0:0:0:1::/64 [interface=]Subnet1InterfaceIndex [publish=]yes

netsh interface ipv6 add route [prefix=]FEC0:0:0:2::/64 [interface=]Subnet2InterfaceIndex [publish=]yes

Where:

• Subnet1InterfaceIndex is the interface index of the adapter on the router computer that is attached to Subnet 1.

• Subnet2InterfaceIndex is the interface index of the adapter on the router computer that is attached to Subnet 2.

For example, if the Subnet 1 and Subnet 2 interface indexes of the router computer are 4 and 3 respectively, the commands are:

netsh interface ipv6 set interface 4 enabled enabled

netsh interface ipv6 set interface 3 enabled enabled

netsh interface ipv6 add route FEC0:0:0:1::/64 4 publish=yes

netsh interface ipv6 add route FEC0:0:0:2::/64 3 publish=yes

Wait about 30 seconds for both the router computer to advertise new site-local prefixes on Subnets 1 and 2 and for Hosts A and B to automatically configure site-local addresses based on these prefixes.

On Host A, type the netsh interface ipv6 show interface command to check for a new IPv6 address for the Ethernet adapter that is based on the site-local prefix of FEC0:0:0:1::/64. On Host B, type the netsh interface ipv6 show interface command to check for a new IPv6 address for the Ethernet adapter that is based on the site-local prefix of FEC0:0:0:2::/64.

On Host A, use the ping command and the site-local address of Host B to ping Host B. For example, if the Host B site-local address is FEC0::2:260:97FF:FE02:6EA5, the command is ping FEC0::2:260:97FF:FE02:6EA5.

For more information about Netsh commands, see Netsh overview and Netsh commands for Interface IPv6.

For additional information about configurations, see IPv6 Configurations.

For information about using IPv6 in a test lab, see Setting up an IPv6 Test Lab.