Tracert

The Tracert tool determines the path taken to a destination. For IPv4, Tracert sends ICMPv4 Echo messages to the destination with incrementally increasing TTL field values. For IPv6, Tracert sends ICMPv6 Echo Request messages to the destination with incrementally increasing Hop Limit field values. Tracert displays the path as the list of nearside router interfaces of the routers in the path between a source host and a destination node.

The Tracert tool in Windows Server 2008 and Windows Vista has been enhanced to support IPv6 in the following ways:

■Tracert can parse both IPv4 and IPv6 address formats.

■If you specify a target host by name, the addresses returned using Windows name resolution techniques can contain both IPv4 and IPv6 addresses—in which case, by default, an IPv6 address is preferred (subject to source and destination address selection).

The following is an example display of the Tracert tool on a computer running Windows Server 2008 or Windows Vista:

F:\>tracert 2001:db8:1:f282:dd48:ab34:d07c:3914

Tracing route to 2001:db8:1:f282:dd48:ab34:d07c:3914 over a maximum of 30 hops

Trace complete.

The following Tracert command-line options support IPv6:

■-R

Forces Tracert to trace the round-trip path by sending the ICMPv6 Echo Request message to the destination, including an IPv6 Routing extension header with the sending node as the next destination

■-S SourceAddr

Forces Tracert to use a specified IPv6 source address

■-4

Forces Tracert to use an IPv4 address when the DNS name query for a host name returns both IPv4 and IPv6 addresses

■-6

Forces Tracert to use an IPv6 address when the DNS name query for a host name returns both IPv4 and IPv6 addresses

42 Understanding IPv6, Second Edition

Note The Tracert -j host-list command-line option is not supported for IPv6.

Pathping

The Pathping tool provides information about network latency and network loss at intermediate hops between a source and destination. For IPv4, Pathping sends multiple ICMPv4 Echo messages to each router between a source and destination over a period of time, and then it computes results based on the packets returned from each router. For IPv6, Pathping sends ICMPv6 Echo Request messages. Because Pathping displays the degree of packet loss at any given router or link, you can determine which routers or subnets might be having network problems. Pathping performs the equivalent of the Tracert tool by identifying which routers are in the path, and then it sends messages periodically to all the routers over a specified time period and computes statistics based on the number returned from each.

The Pathping tool in Windows Server 2008 and Windows Vista has been enhanced to support IPv6 in the following ways:

■Pathping can parse both IPv4 and IPv6 address formats.

■If you specify a target host by name, the addresses returned using Windows name resolution techniques can contain both IPv4 and IPv6 addresses—in which case, by default, an IPv6 address is preferred (subject to source and destination address selection).

The following is an example display of the Pathping tool on a computer running Windows Server 2008 or Windows Vista:

F:\>pathping 2001:db8:1:f282:dd48:ab34:d07c:3914

Tracing route to 2001:db8:1:f282:dd48:ab34:d07c:3914 over a maximum of 30 hops

0server1.example.microsoft.com [2001:db8:1:f282:204:5aff:fe56:1006]

12001:db8:1:f282:dd48:ab34:d07c:3914

The following Pathping command-line options support IPv6:

■-4

Forces Pathping to use an IPv4 address when the DNS name query for a host name returns both IPv4 and IPv6 addresses

■-6

Forces Pathping to use an IPv6 address when the DNS name query for a host name returns both IPv4 and IPv6 addresses

Note The Pathping -g host-list command-line option is not supported for IPv6.

Netstat

The Netstat tool displays active TCP connections, ports on which the computer is listening, Ethernet statistics, the IPv4 routing table, IPv4 statistics (for the IP, ICMP, TCP, and UDP protocols), the IPv6 routing table, and IPv6 statistics (for the IPv6, ICMPv6, TCP over IPv6, and UDP over IPv6 protocols).

The following is an example display of the Netstat tool on a computer running Windows Server 2008 or Windows Vista: