System Administration Guide: IP Services

IPv6 Extensions to Existing Utilities

User-level interface changes also include extensions to the following utilities:

The ifconfig(1M) utility has also changed. See IPv6 Extensions to the ifconfig Utility for a description.


In addition to displaying IPv4 network status, netstat can display IPv6 network status as well. You can choose which protocol information to display by setting the DEFAULT_IP value in the /etc/default/inet_type file and the -f command-line option. With a permanent setting of DEFAULT_IP, you can ensure that netstat displays only IPv4 information. You can override this setting with the -f option. For more information on the inet_type file, see the inet_type(4) man page.

The new -p option displays the net-to-media table, which is the ARP table for IPv4 and neighbor cache for IPv6. See the netstat(1M) man page for details. See How to Display Network Status for descriptions of procedures that use this command.


The snoop command can capture both IPv4 and IPv6 packets. This command can display IPv6 headers, IPv6 extension headers, ICMPv6 headers, and neighbor discovery protocol data. By default, the snoop command displays both IPv4 and IPv6 packets. By specifying the ip or ip6 protocol keywords, the snoop command displays only IPv4 or IPv6 packets. The IPv6 filter option enables you to filter through all packets (both IPv4 and IPv6), displaying only the IPv6 packets. See the snoop(1M) man page for details. See How to Monitor Only IPv6 Network Traffic for a description of procedures that use this command.


This utility now operates on both IPv4 and IPv6 routes. By default, route operates on IPv4 routes. If you use the option -inet6 on the command line immediately after the route command, operations are performed on IPv6 routes. See the route(1M) man page for details.


The ping command can use both IPv4 and IPv6 protocols to probe target hosts. Protocol selection depends on the addresses that are returned by the name server for the specific target host. By default, if the name server returns an IPv6 address for the target host, the ping command uses the IPv6 protocol. If the server returns only an IPv4 address, the ping command uses the IPv4 protocol. You can override this action by using the -A command-line option to specify which protocol to use.

Additionally, you can ping all the addresses of a multihomed target host by using the -a command-line option. See the ping(1M) man page for details. See How to Probe All Multihomed Host Addresses for a description of a procedure that uses this command.


You can use the traceroute command to trace both the IPv4 and IPv6 routes to a specific host. From a protocol perspective, traceroute uses the same algorithm as ping. Use the -A command-line option to override this selection. You can trace each individual route to every address of a multihomed host by using the -a command-line option. See the traceroute(1M) man page for details.