HP-UX IPv6 Transport Administrator Guide HP-UX 11i v3 (5992-6426, May 2013)

Migrating Name and IPv6 Address Lookup
Most sites test IPv6 on a development subnetwork before deploying it on a larger scale.
These sites typically add IPv6 address and host names to the /etc/hosts files on IPv6
hosts, then change their hosts lookup policy to search files.
HP recommends that you maintain at least a minimal /etc/hosts file that includes
important addresses like gateways, root servers, and your host’s own IP address. HP
also recommends that you include the word files in the hosts and ipnodes lines of
/etc/nsswitch.conf to help ensure a successful system boot using the /etc/hosts
file when DNS is not available.
Migrating from IPv4 to IPv6
IPv6 is the next generation Internet protocol and is designed to be a replacement for
IPv4. However, it is expected that IPv6 adoption will be gradual and there will be a
lengthy transition period during which IPv4 and IPv6 protocols will have to coexist. The
IETF (ngtrans working group) has developed a number of transition mechanisms that
facilitates IPv6 deployment.
The main goals of these transition mechanisms are to allow newly deployed IPv6 hosts
and routers to inter-operate with existing IPv4 hosts and routers and allow isolated IPv6
hosts and routers to communicate with each other using the existing IPv4 infrastructure.
HP-UX 11i v3 IPv6 transport supports the following three transition mechanisms:
• Dual stack: This mechanism provides complete concurrent support for both IPv4 and
IPv6 protocols in hosts and routers. It allows networks to support both IPv4
applications and IPv6 applications.
• Tunneling: Tunneling encapsulates IPv6 packets within IPv4 packets. IPv6 transmission
across the IPv4 network is transparent. In HP-UX 11i v3 configured (point-to-point)
tunneling is supported. In addition to IP6-in-IP tunneling support, IP6-in-IP6 and
IP-in-IP6 tunnels are also supported.
• “6to4”: Isolated IPv6 nodes and networks can communicate over an IPv4 network,
without explicitly configuring tunnels, by using the “6to4” mechanism (RFC 3056).
“6to4” effectively treats the IPv4 wide area network as a unicast point-to-point link
layer. “6to4” requires no end-node reconfiguration and minimal router configuration.
Tunneling
Tunneling enables IPv6 hosts and routers to connect with other IPv6 hosts and routers
over an existing IPv4 network. Dual stack hosts and routers can tunnel IPv6 packets over
regions of IPv4 routing topology by encapsulating them within IPv4 packets. The
encapsulated packets travel across an IPv4 Internet until they reach their destination host
or router. The IPv6-aware host or router decapsulates the IPv6 datagrams, forwarding
them as needed. The IPv6 transmission across the IPv4 Internet is transparent. This type
of tunneling is referred to as IP6-in-IP.
54 IPv6 Software and Interface Technology