NAME
hf6to4
- setup automatic 6to4 IPv6 tunnelling
SYNOPSIS
hf6to4
[-vn]
command
DESCRIPTION
The
hf6to4
script can be used to setup IPv6 on your home machine and
network for exploring IPv6 without any registrations. 6to4 is a
mechanism by which your IPv6 address(es) are derived from an assigned
IPv4 address, and which involves automatic tunnelling to one or more
remove 6to4 relay routers, which will then forward your v6 packets on the 6bone.
Replies are routed back to you over IPv4 via (possibly) other
6to4 relay routers. As such, IPv6-in-IPv4-encapsulated
packets are accepted from all v4-hosts. See
stf(4)
for security discussion.
From your (single) IPv4 address, you get a whole IPv6 /48 network,
which allows you to split your network in 2^16 subnets, with 2^64
hosts each. You need to setup routing for your internal network
properly, help is provided for setting up the border router here.
This script takes the burden to calculate your IPv6 address from
existing IPv4 address and runs the commands to setup (and tear down)
automatic 6to4 IPv6 tunnelling. In a separate step, router
advertisement for the inside network can be started and stopped.
Possible options are:
- -n
-
Do not. Only print the commands that would be run, but do not execute
them.
- -v
-
Verbose operation. Print the commands that are about to be run, before
running them. Displays some additional information.
- -h
-
Show usage.
Possible commands are:
- start
-
Configure 6to4 IPv6. The
stf(4)
interface is configured, and a default route to a remote 6to4
gateway is established. In addition, the internal
network interface is assigned an address.
- stop
-
Stops 6to4 IPv6. All addresses are removed from the
stf(4)
device, and the default route is removed.
- rtadvd-start
-
Starts router advertizement and IPv6 packet forwarding,
turning the machine into a IPv6 router.
Clients just need to be told to accept router advertizements, i.e.
the
`net.inet6.ip6.accept_rtadv'
sysctl needs to be set to
`1'.
On NetBSD, you can arrange that by setting
``ip6mode=autohost''
in
/etc/rc.conf.
- rtadvd-stop
-
Stops router advertizement and IPv6 packet forwarding.
rtadvd(8)
is stopped.
REQUIREMENTS
Besides IPv4 connectivity, you need support for IPv6 and the
stf(4)
device in your kernel. While the GENERIC
NetBSD
1.5 kernel does support IPv6, it does not contain support for the
stf(4)
device.
Make sure you have the following options in your kernel config file:
-
options INET # IP + ICMP + TCP + UDP
options INET6 # IPV6
pseudo-device stf 1 # 6to4 IPv6 over IPv4 encapsulation
In systems that run past-1.5,
you will have to explicitly create an
stf(4)
device after compiling it in the kernel. You do this by running
the following command before calling the
hf6to4
script:
-
ifconfig stf0 create
As an alternative, you can also put the following lines into
/etc/rc.conf:
-
net_interfaces="stf0"
ifconfig_stf0="create"
See also the comment on setting up IPv6-clients
`behind'
your 6to4 router for the
rtadvd-start
command!
CONFIGURATION
The
hf6to4
script reads its configuration from a config file named
hf6to4.conf.
The
hf6to4.conf
file is in
sh(1)
syntax, and contains several
variables that can be tuned to adjust your setup. Default values
should work for use on a modem/DSL dialup.
- out_if
-
The outbound interface that has a valid IPv4 address
assigned, that can be used to derive the IPv6
addresses from. Usually
``ppp0''
for a modem setup, or your ethernet interface if you have
IPv4 connectivity via LAN. This
can't be empty, and is assigned the IPv6 address
2002:x:x:v6_net:hostbits6, see below.
- in_if
-
The inside interface. If non-empty, this interface is
assigned the IPv6 address
2002:x:x:v6_innernet:hostbits6, see below.
This is only useful on machines that
have more than one network interfaces, e.g. with a modem and a
local ethernet.
- v6_net
-
The subnet address you want to use on the address of
your outbound interface. Defaults to
``1''.
- v6_innernet
-
The subnet address you want to use on the address of
your inbound interface. Defaults to
``2''.
- hostbits6
-
The lower 64 bits of both the inbound and outbound interface's
addresses.
- peer
-
Name of the remote 6to4 server that'll take our
IPv6-in-IPv4 encapsulated packets and route them on
via IPv6. A special value of
``6to4-anycast''
can be used for the anycast service defined in RFC 3068.
Other possible values are given in the example config file.
- remoteadr4, remoteadr6
-
If the
peer
variable is set to the relay router's name, DNS lookups for A and AAAA
records will be made to
determine its IPv4 and IPv6 address. To avoid these lookups, the variables
remoteadr4
and
remoteadr6
can be set to strings containing the numerical IPv4 and IPv6 numbers
directly.
EXAMPLES
The
hf6to4
script can be run automatically by
pppd(8)
when a connection is made. For this, put the following into
/etc/ppp/ip-up:
-
( /usr/pkg/sbin/hf6to4 stop
/usr/pkg/sbin/hf6to4 start ) &
To shut down properly, put this into
/etc/ppp/ip-down:
-
/usr/pkg/sbin/hf6to4 stop
SEE ALSO
stf(4),
``6to4 IPv6 Explained''
at
http://www.feyrer.de/NetBSD/6to4.html,
NetBSD
IPv6 Documentation at
http://www.netbsd.org/Documentation/network/ipv6/,
RFC 3068.
HISTORY
The
hf6to4
utility and manpage were written by
Hubert Feyrer .
BUGS
On systems running past-1.5, the
``ifconfig stf0 create''
should be run automatically.