HP-UX IPv6 Transport Administrator's Guide for TOUR 2.0 (April 2004, rev 2)
IPv6 Software and Interface Technology
Migrating from IPv4 to IPv6
Chapter 7 81
As shown in the “6to4” topology example of Figure 7-3:
6to4 host: An IPv6 host that has at least one “6to4” address configured.
The "6to4" address is autoconfigured using the "6to4" prefix advertised
by the "6to4" router. It has a default route to the "6to4" router. All
non-local "6to4" addressed packets and native IPv6 packets are sent to
the "6to4" router.
"6to4" router: An IPv6/IPv4 border router that forwards "6to4"
addressed traffic between "6to4" hosts within a site and other "6to4"
routers or to "6to4" relay routers across IPv4 internet. "6to4" routers
need to have at least one public IPv4 address and the "6to4" prefix is
derived from the public IPv4 address. The "6to4" router advertises the
"6to4" prefix on its attached link. It performs the encapsulation and
decapsulation functions.
"6to4" relay router: An IPv6/IPv4 router that performs the functions of
the "6to4" router and forwards "6to4" addressed traffic between "6to4"
routers on the IPv4 internet and IPv6 hosts on the IPv6 internet.
An IPv6 interior routing protocol, such as routing information protocol
next generation (RIPng), is used for routing IPv6 in a "6to4" domain.
IPv4 exterior routing protocol handles the routing of tunneled IPv4
packets between "6to4" routers and relay routers. In addition, for
forwarding native IPv6 addressed packets, a default route from the
"6to4" router to the relay router can be setup or IPv6 exterior routing
protocol can be used between "6to4" routers and relay routers.
“6to4” Security Considerations By default, “6to4” routers and relay
routers accept and decapsulate traffic from any source. This potentially
allows malicious parties to get around access controls and spoof
addresses, to perform denial of service attacks. Before setting up a
tunnel from a “6to4” router to an external “6to4” relay router, review the
internet draft Security Considerations for 6to4 at http://www.ietf.org.
Configuration Example: For the topology example shown in
Figure 7-3, the following sample ifconfig commands will (ephemerally)
configure the HP-UX 11i v2 dual stack routers to handle “6to4”:
On R1: ifconfig iptu0 inet6 tunnel 6to4 tsrc 15.1.1.1
On R2: ifconfig iptu1 inet6 tunnel 6to4 tsrc 16.2.2.2
On R3: ifconfig iptu2 inet6 tunnel 6to4 tsrc 17.3.3.3