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	1	.\" $NetBSD: 6to4.8,v 1.5 2001/12/03 19:03:21 wiz Exp $
	2	.Dd May 21, 2002
	3	.Dt ip6config 8
	4	.Os
	5	.Sh NAME
	6	.Nm ip6config
	7	.Nd Configure IPv6 and 6to4 IPv6 tunnelling
	8	.Sh SYNOPSIS
	9	.Nm
	10	.Op Fl h
	11	.Ar command interface
	12	.Sh DESCRIPTION
	13	The
	14	.Nm
	15	script can be used to start up or shut down IPv6 on active interfaces. It
	16	can also be used to configure a 6to4 tunnel and start or stop router
	17	advertisement.
	18	.Pp
	19	When IPv6 is enabled on an interface the protocol is attached to the
	20	interface, at which point the default settings in the kernel allow it
	21	to acquire a link-local address and listen for router advertisements.
	22	.Pp
	23	6to4 is a mechanism by which your IPv6 address(es) are derived from an
	24	assigned IPv4 address, and which involves automatic tunnelling to one or
	25	more remove 6to4 hubs, which will then forward your v6 packets on the
	26	6bone etc. Replies are routed back to you over IPv4 via (possibly) other
	27	6to4 capable remote gateways. As such, IPv6-in-IPv4-encapsulated
	28	packets are accepted from all v4-hosts.
	29	.Pp
	30	From your (single) IPv4 address, you get a whole IPv6 /48 network,
	31	which allows you to split your network in 2^16 subnets, with 2^64
	32	hosts each. You need to setup routing for your internal network
	33	properly, help is provided for setting up the border router here.
	34	.Pp
	35	This script takes the burden to calculate your IPv6 address from
	36	existing IPv4 address and runs the commands to setup (and tear down)
	37	automatic 6to4 IPv6 tunnelling.
	38	.Pp
	39	Finally, router advertisement for an internal network can be started
	40	and stopped. This uses sysctl to set net.inet6.ip6.forwarding and
	41	net.inet6.ip6.accept_rtadv to the proper values for routing.
	42	.Pp
	43	Possible options are:
	44	.Bl -tag -width xxx
	45	.It Fl h
	46	Show usage.
	47	.El
	48	.Pp
	49	Possible commands are:
	50	.Bl -tag -width start-rtadvd
	51	.It Sy start-v6
	52	Start IPv6 on given interface using default kernel settings. Attaches
	53	protocol to the interface. If interface is "all", all valid interfaces
	54	will be configured.
	55	.It Sy stop-v6
	56	Stop IPv6 on given interface. Detaches protocol from the interface. If
	57	interface is "all", all valid interfaces will be configured.
	58	.It Sy start-stf
	59	Configure 6to4 IPv6. The
	60	.Xr stf 4
	61	interface is configured, and a default route to a remote 6to4
	62	gateway is established. In addition, the internal
	63	network interface is assigned an address.
	64	.It Sy stop-stf
	65	Stops 6to4 IPv6. All addresses are removed from the
	66	.Xr stf 4
	67	device, and the default route is removed.
	68	.It Sy start-rtadvd
	69	Starts router advertizement and IPv6 packet forwarding,
	70	turning the machine into a IPv6 router.
	71	.Xr rtadvd 8
	72	is invoked with a custom config file created under
	73	.Pa /var/run .
	74	Clients just need to be told to accept router advertizements, i.e.
	75	the
	76	.Sq net.inet6.ip6.accept_rtadv
	77	sysctl needs to be set to
	78	.Sq 1 .
	79	You can arrange that by setting
	80	.Dq ip6mode=autohost
	81	in
	82	.Pa /etc/rc.conf .
	83	.It Sy stop-rtadvd
	84	Stops router advertizement and IPv6 packet forwarding.
	85	.Xr rtadvd 8
	86	is stopped, and the
	87	.Xr rtadvd.conf 5
	88	config file is removed from
	89	.Pa /var/run .
	90	.El
	91	.Sh REQUIREMENTS
	92	Besides IPv4 connectivity, you need support for IPv6 and the
	93	.Xr stf 4
	94	device in your kernel. This is provided beginning with Darwin
	95	Kernel Version 6.0.
	96	.Pp
	97	No special values are needed in
	98	.Pa /etc/rc.conf
	99	to run this script, but see comment on setting up IPv6-clients
	100	.Sq behind
	101	your 6to4 router for the
	102	.Sy rtadvd-start
	103	command!
	104	.Sh CONFIGURATION
	105	The default IPv6 configuration for an interface assigns a link-local
	106	address to it and sets the interface to receive router advertisements.
	107	No further configuration is necessary for basic functionality.
	108	However, various settings can be modified by using sysctl.
	109	.Pp
	110	The
	111	.Nm
	112	script reads its 6to4 configuration from a config file named
	113	.Pa 6to4.conf .
	114	The
	115	.Pa 6to4.conf
	116	file is in
	117	.Xr perl 1
	118	syntax, and contains several
	119	variables that can be tuned to adjust your setup.
	120	.Bl -tag -width start-rtadvd
	121	.It Sy in_if
	122	The inside interface. If non-empty, this interface is
	123	assigned the IPv6 address
	124	2002:x:x:v6_innernet:hostbits6, see below.
	125	This is only useful on machines that
	126	have more than one network interface, e.g. with a modem and a
	127	local ethernet.
	128	.It Sy v6_net
	129	The subnet address you want to use on the address of
	130	your outbound interface. Defaults to
	131	.Dq 1 .
	132	.It Sy v6_innernet
	133	The subnet address you want to use on the address of
	134	your inbound interface. Defaults to
	135	.Dq 2 .
	136	.It Sy hostbits6
	137	The lower 64 bits of both the inbound and outbound interface's
	138	addresses.
	139	.It Sy peer
	140	Name of the remote 6to4 server that'll take our
	141	IPv6-in-IPv4 encapsulated packets and route them on
	142	via IPv6. A special value of
	143	.Dq 6to4-anycast
	144	can be used for the anycast service defined in RFC 3068.
	145	Other possible values are given in the example config file.
	146	.El
	147	.Sh SEE ALSO
	148	.Xr stf 4 ,
	149	.Dq 6to4 IPv6 Explained
	150	at
	151	.Pa http://www.feyrer.de/NetBSD/6to4.html ,
	152	.Nx
	153	IPv6 Documentation at
	154	.Pa http://www.netbsd.org/Documentation/network/ipv6/ ,
	155	RFC 3068.
	156	.Sh HISTORY
	157	The
	158	.Nm
	159	6to4 utility and manpage portions were written by
	160	Hubert Feyrer <hubert@feyrer.de> for NetBSD.