address
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...
The document defines a method for assigning an interim unique IPv6
address prefix to any site that currently has at least one globally
unique IPv4 address ...
... IPv6
address prefix to any site that currently has at least one globally
unique IPv4 address, and specifies an encapsulation mechanism for
transmitting ...
... be applied to an individual IPv6 host or very small site, as long as
it has at least one globally unique IPv4 address. However, the
latter case raises serious scaling issues which are the subject of
...
... method do not require IPv4-
compatible IPv6 addresses [MECH] or configured tunnels. In this way
...
... border
routers, without specific host modifications except a suggested
address selection default. Only a modest amount of router
configuration is required.
...
... host:
an IPv6 host which happens to have at least one 6to4 address.
In all other respects it is a standard IPv6 host.
...
...
Note: an IPv6 node may in some cases use a 6to4 address for a
configured tunnel. Such a node ...
... node may function as an IPv6 host using a
6to4 address on its configured tunnel interface, and it may also
...
... 6to4 site:
a site running IPv6 internally using 6to4 addresses, therefore
containing at least one 6to4 host ...
... 6to4 router configured to support transit routing between
6to4 addresses and native IPv6 addresses.
...
... valid, globally
unique 32-bit IPv4 address, referred to in this document as V4ADDR.
This address ...
... IPv4 address, referred to in this document as V4ADDR.
This address MUST be duly allocated to the site by an address
registry ...
... V4ADDR.
This address MUST be duly allocated to the site by an address
registry (possibly via a service provider ...
... AGGR] for the 6to4 scheme.Its numeric value is 0x0002, i.e., it is
2002::/16 when expressed as an IPv6 address prefix.
...
...
The subscriber site is then deemed to have the following IPv6 address
prefix, without any further assignment procedures being necessary:
...
... like any other valid IPv6 prefix, e.g., for automated address
assignment and discovery according to the normal mechanisms such as
[CONF, DISC ...
... 6OVER4].
Note that if the IPv4 address is assigned dynamically, the
corresponding IPv6 prefix will also be dynamic in nature, with the
...
... Address Selection ...
... 6to4 in complex topologies, source
and destination address selection must be appropriately implemented.
If the source IPv6 host ...
... source IPv6 host sending a packet has at least one 2002::
address assigned to it, and if the set of IPv6 addresses returned by
the DNS ...
... host sending a packet has at least one 2002::
address assigned to it, and if the set of IPv6 addresses returned by
the DNS for the destination host ...
... DNS for the destination host contains at least one 2002::
address, then the source host must make an appropriate choice of the
source and destination addresses ...
... address, then the source host must make an appropriate choice of the
source and destination addresses to be used. The mechanisms for
address selection in general are under study at the time of writing
...
... source and destination addresses to be used. The mechanisms for
address selection in general are under study at the time of writing
[SELECT]. Subject ...
...
If one host has only a 6to4 address, and the other one has both a
6to4 and a native IPv6 address ...
... 6to4 address, and the other one has both a
6to4 and a native IPv6 address, then the 6to4 address should be used
for both.
...
... If both hosts have a 6to4 address and a native IPv6 address, then
either the 6to4 address should be used for both, or the native IPv6
address ...
... 6to4 address and a native IPv6 address, then
either the 6to4 address should be used for both, or the native IPv6
address should be used for both. The choice should be configurable.
The default configuration should be native IPv6 ...
... IPv6 address, then
either the 6to4 address should be used for both, or the native IPv6
address should be used for both. The choice should be configurable.
The default configuration should be native IPv6 for both.
...
... header
contains the Destination and Source IPv4 addresses. One or both of
these will be identical to the V4ADDR field of an IPv6 prefix ...
... Header Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Address ...
... Source Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Options | Padding |
...
... Link-Local Address and NUD ...
... encapsulation would, if needed, be formed as described in Section 3.7
of [MECH]. However, no scenario is known in which such an address
would be useful, since a peer 6to4 gateway ...
... Section 2. It will therefore create DNS records for these addresses.
For example, site A which owns IPv4 address 192.1.2.3 will create ...
... DNS records for these addresses.
For example, site A which owns IPv4 address 192.1.2.3 will create DNS
records with the IPv6 prefix ...
... IPv6 prefix {FP=001,TLA=0x0002,NLA=192.1.2.3}/48
(i.e., 2002:c001:0203::/48). Site B which owns address 9.254.253.252
will create DNS records ...
... DNS entry for a host on site
A, or otherwise obtains its address, it obtains an address with the
prefix ...
...
Within a 6to4 site, addresses with the 2002::/16 prefix, apart from
those with the local 2002:V4ADDR ...
... prefix, will be handled like
any other non-local IPv6 address, i.e., by a default or explicit
route towards the 6to4 border router ...
...
It is RECOMMENDED that in any case each site should use only one IPv4
address per 6to4 router, and that should be the address assigned to
...
... It is RECOMMENDED that in any case each site should use only one IPv4
address per 6to4 router, and that should be the address assigned to
the external interface of the 6to4 router ...
... 6to4 router. Single-homed sites
therefore SHOULD use only one IPv4 address for 6to4 routing. Multi-
...
... native or tunneled IPv6 using normal IPv6 TLA address space. The
6to4 sites will need connectivity to these native IPv6 ...
... IPv6 routers which possess both 6to4 and native IPv6 addresses.
Although they behave essentially as standard IPv6 routers, for the
...
... DNS entries will reflect this
and DNS lookups will return multiple addresses. If two such sites
need to interoperate, whether the 6to4 route ...
... route or the native route will
be used depends on IPv6 address selection by the individual hosts (or
even applications).
...
... prefix according to some rule for multiple
prefixes, it will simply send packets to an IPv6 address formed with
the prefix {FP ...
... {FP=001,TLA=0x0002,NLA=9.254.253.252}/48 for two-way connectivity to
be possible. The address selection mechanism of Section 2.1 will
ensure this.
...
... IPv6 packets received by the relay router whose next hop IPv6 address
matches 2002::/16 will be routed to its 6to4 pseudo ...
... IPv6 route ::/0 would point to the relay router's address under
prefix 2002:09fe:fdfc::/48).
...
... interface. In the simplest case, a default route to the whole
IPv6 address space could be advertised. When multiple relay routers
are in use, more specific routing prefixes ...
... IPv6 routing mechanisms. If the final destination is a 6to4 address,
it will be considered as the next hop for the purpose of this rule.
...
... next hop for the purpose of this rule.
If the final destination is not a 6to4 address, and is not local, the
next hop indicated by routing ...
... tunnels could be autoconfigured using
an IPv4 anycast address, but this is outside of the scope of this
document. Alternatively a tunnel broker can be used. This scenario
...
...
If the above rules for routing advertisements and address selection
are followed, then a site can migrate from using 6to4 to using native
...
... route pointing to
that relay router's 6to4 address. If an exterior routing protocol
such as BGP4+ is in use, the site's 6to4 router ...
... border router configuration
and the DNS configuration. At this point, an address selection rule
will determine when 6to4 and when native IPv6 ...
...
If the site concerned has very limited global IPv4 address space, and
is running an IPv4 network address ...
... IPv4 address space, and
is running an IPv4 network address translator (NAT), all of the above
mechanisms remain valid ...
... IPv6 router including the 6to4 mechanism. The address
used for V4ADDR will simply be a globally unique IPv4 address ...
... address
used for V4ADDR will simply be a globally unique IPv4 address
allocated to the NAT. In the example of Section 5.1 above, the 6to4
routers ...
... IPv6 /48 prefix, automatically, behind
the IPv4 address of the NAT. Thus every host behind the NAT ...
... NAT can
become an IPv6 host with no need for additional address space
allocation, and no intervention by the Internet service provider. No
...
... allocation, and no intervention by the Internet service provider. No
address translation is needed by these IPv6 hosts.
...
... host is more than one NAT hop
away from the globally unique IPv4 address space, since only the
outermost NAT has a unique IPv4 address ...
... IPv4 address space, since only the
outermost NAT has a unique IPv4 address. All IPv6 hosts in this
situation must use addresses ...
... IPv4 address. All IPv6 hosts in this
situation must use addresses derived from the 2002: prefix
constructed from the global IPv4 address ...
... addresses derived from the 2002: prefix
constructed from the global IPv4 address of the outermost NAT. The
IPv4 addresses ...
... IPv4 address of the outermost NAT. The
IPv4 addresses of the inner NATs are not globally unique and play no
part in the 6to4 ...
... RSIP function
provides fine-grained management of dynamic global IPv4 address
allocation and the 6to4 function provides a stable IPv6 ...
... 6to4 function provides a stable IPv6 global
address to each host. As with NAT, the IPv4 address ...
... address to each host. As with NAT, the IPv4 address used to
construct the site's 2002: prefix will be one of the global
...
... construct the site's 2002: prefix will be one of the global
addresses of the RSIP border router.
...
... prefixes. The V4ADDR MUST be
a duly allocated global IPv4 address, which MUST be unique within the
private network. The Intranet ...
... private network. The Intranet thereby obtains globally unique IPv6
addresses even if it is internally using private IPv4 addresses [RFC1918].
...
... private network. The Intranet thereby obtains globally unique IPv6
addresses even if it is internally using private IPv4 addresses [RFC1918].
...
... FP=001,TLA=0x0002,NLA=V4ADDR}/48, where V4ADDR is the IPv4 address
of the relay router. Such a route ...
... ANYCAST] is compatible with
2002:: prefixes, i.e., anycast addresses formed with such prefixes
may be used inside a 6to4 ...
... is felt to be more likely than IPv4 spoofing), then additional source
address based packet filtering could be applied. A possible
plausibility check is whether the encapsulating IPv4 address ...
... source
address based packet filtering could be applied. A possible
plausibility check is whether the encapsulating IPv4 address is
consistent with the encapsulated 2002:: address ...
... IPv4 address is
consistent with the encapsulated 2002:: address. If this check is
applied, exceptions to it must be configured to admit traffic from
...
... In any case, any 6to4 traffic whose source or destination address
embeds a V4ADDR which is not in the format of a global unicast ...
... V4ADDR which is not in the format of a global unicast
address MUST be silently discarded by both encapsulators and
decapsulators. Specifically, this means that IPv4 addresses defined
...
... address MUST be silently discarded by both encapsulators and
decapsulators. Specifically, this means that IPv4 addresses defined
in [RFC1918], broadcast ...
... Hinden., R, O'Dell, M. and S. Deering, "An IPv6 Aggregatable Global Unicast Address Format", RFC 2374hist(-> 3587), July 1998. ...
... Thomson, S. and T. Narten, "IPv6 Stateless Address Autoconfiguration", RFC 2462draft, December 1998. ...
... Draves, R., "Default Address Selection for IPv6", Work in Progress. ...
... Rekhter, Y., Moskowitz, R., Karrenberg, D., de Groot, G. and E. Lear, "Address Allocation for Private Internets", BCP 5, RFC 1918, February 1996. ...
... Authors' Addresses ...
... copyrights, patents or patent applications, or other proprietary
rights which may cover technology that may be required to practice
this standard. Please address the information to the IETF Executive
Director.
...