IN.NDPD(1M)IN.NDPD(1M)NAMEin.ndpd - daemon for IPv6 autoconfiguration
/usr/lib/inet/in.ndpd [-adt] [-f config_file]
DESCRIPTIONin.ndpd provides both the host and router autoconfiguration components
of Neighbor Discovery for IPv6 and Stateless and Stateful Address Auto‐
configuration for IPv6. In particular, in.ndpd implements:
o router discovery;
o prefix discovery;
o parameter discovery;
o invocation of stateful address autoconfiguration;
o stateless address autoconfiguration; and
o privacy extensions for stateless address autoconfiguration.
Other aspects of Neighbor Discovery are implemented by ip6(7P), includ‐
o address resolution;
o neighbor unreachability detection; and
The duplicate address detection function is implemented by the system
in.ndpd is managed by the service management facility (SMF), by means
of the service identifier:
If the /etc/inet/ndpd.conf file does not exist or does not set the
variable AdvSendAdvertisements to true for a network interface, then
in.ndpd will make the node a host for that interface, that is, sending
router solicitation messages and then using router advertisement mes‐
sages it receives to autoconfigure the node. Note that in.ndpd only
autoconfigures the addresses of global or site-local scope from the
If AdvSendAdvertisements is set to true for an interface, then in.ndpd
will perform router functions on that interface, that is, sending
router advertisement messages to autoconfigure the attached hosts, but
not use any advertisements it receives for autoconfiguration. However,
when sending advertisements, in.ndpd will use the advertisements it
sends itself to autoconfigure its prefixes.
Stateless autoconfiguration requires no manual configuration of hosts,
minimal (if any) configuration of routers, and no additional servers.
The stateless mechanism enables a host to generate its own addresses
and uses local information as well as non-local information that is
advertised by routers to generate the addresses. in.ndpd will plumb
logical interfaces for each of these addresses.
Stateful autoconfiguration involves the dhcpagent(1M) daemon and the
use of the DHCPv6 protocol. The dhcpagent daemon is responsible for
plumbing the logical interfaces for the acquired addresses, maintaining
the leases, and handling duplicate addresses. in.ndpd starts the dhcpa‐
gent daemon automatically and signals when DHCPv6 should be started.
in.ndpd also detects when dhcpagent configures the logical interfaces,
and sets the appropriate prefix length on each according to received
Routing Advertisement messages. in.ndpd will not stop dhcpagent; use
ifconfig(1M) to control dhcpagent if necessary.
Temporary addresses that are autoconfigured for an interface can also
be implemented. A temporary address token is enabled for one or more
interfaces on a host. However, unlike standard, autoconfigured IPv6
addresses, a temporary address consists of the site prefix and a ran‐
domly generated 64 bit number. This random number becomes the inter‐
face ID segment of the IPv6 address. A link-local address is not gener‐
ated with the temporary address as the interface ID.
If the kernel detects a duplicate temporary address, in.ndpd will auto‐
matically choose another.
Routers advertise all prefixes that have been assigned on the link.
IPv6 hosts use Neighbor Discovery to obtain a subnet prefix from a
local router. Hosts automatically create IPv6 addresses by combining
the subnet prefix with an interface IDs that is generated from an
interface's MAC address. In the absence of routers, a host can generate
only link-local addresses. Link-local addresses can only be used for
communication with nodes on the same link.
For information on how to enable IPv6 address autoconfiguration, see
Supported options and equivalent SMF service properties are listed
below. SMF service properties are set using a command of the form:
# routeadm -m ndp:default key=value
Turn off stateless and stateful address auto configuration. When
set, the daemon does not autoconfigure any addresses and does not
renumber any addresses. This option does the same thing as the fol‐
lowing lines in ndpd.conf(4):
ifdefault StatefulAddrConf off
ifdefault StatelessAddrConf off
Use of this option is equivalent to setting the stateless_addr_conf
property to false.
Turn on large amounts of debugging output on stdout. When set, the
program runs in the foreground and stays attached to the control‐
ling terminal. Use of this option is equivalent to setting the
debug property to true.
Use config_file for configuration information instead of the
default /etc/inet/ndpd.conf. Use of this option is equivalent to
setting the config_file property to the configuration file to be
Turn on tracing (printing) of all sent and received packets tostd‐
out. When set, the program runs in the foreground and stays
attached to the controlling terminal. As such, this option cannot
be run under the SMF.
Configuration file. This file is not necessary
on a host, but it is required on a router to
enable in.ndpd to advertise autoconfiguration
information to the hosts.
SEE ALSOdhcpagent(1M), ifconfig(1M), routeadm(1M), svcadm(1M), ndpd.conf(4),
attributes(5), icmp6(7P),ip6(7P), attributes(5), smf(5)
Narten, T., Nordmark, E., Simpson, W.RFC 2461, Neighbor Discovery for
IP Version 6 (IPv6). The Internet Society. December 1998.
Thomson, S., Narten, T. RFC 2462, IPv6 Stateless Address Autoconfigura‐
tion. The Internet Society. December 1998.
Narten, T., and Draves, R. RFC 3041, Privacy Extensions for Stateless
Address Autoconfiguration in IPv6. The Internet Society. January 2001.
Receipt of a SIGHUP signal will make in.ndpd restart and reread
The in.ndpd daemon service is managed by the service management facil‐
ity, smf(5), under the service identifier:
Administrative actions on this service, such as enabling, disabling, or
requesting restart, can be performed using svcadm(1M) or routeadm(1M).
Jan 10, 2007 IN.NDPD(1M)