Technical data

ServerIron ADX NAT64 Configuration Guide 29
53-1002288-02
DRAFT: BROCADE CONFIDENTIAL
Chapter
3
IPv4-only client to IPv6 resource
Overview
A NAT46 gateway enables IPv4-only clients and IPv6 resources to communicate with each other via
address and packet translation. This translation is performed in stateless mode on a NAT46
gateway using a mapping table. The mapping table matches IPv4 request packets from the client
sent to the gateway to an IPv6 destination address of the IPv6 resource.This mode requires the
following components
• NAT64 IPv4 Prefix – The NAT64 IPv4 prefix provides a range of IPv4 addresses on the NAT64
gateway that can be used to represent IPv6 resources. It is created by defining an IPv4 prefix
with a subnet mask. Any IPv4 address within the defined subnet can then be assigned to an
IPv6 resource that is being made available through the gateway.
• NAT64 IPv6 Prefix – The NAT64 IPv6 prefix is used to create a unique IPv6 address for IPv6
resources it makes available through the gateway. The defined NAT64 IPv6 prefix is
concatenated with an IPv4 address selected from within the subnet defined by the NAT64
IPv4-only prefix.
• DNS64 server – This component (not supplied by Brocade) is responsible for providing the IPv4
clients with the IPv4 addresses defined for IPv6 resources that the client wants to utilize.
These IPv4 addresses are defined within the range specified by the NAT64 IPv4 prefixes and
are assigned by the administrator of the DNS64 server. The DNS64 server also maintains all of
the IPv6 addresses of the resources within the IPv6-only network and makes them available to
the NAT46 gateway.
• NAT46 gateway – This component is installed on a ServerIron ADX. It is reached by the IPv4
client using an IPv4 address supplied to it by the DNS server. When packets from the IPv4
client reach the NAT46 gateway, they are mapped to an IPv6 address for the resource that they
want to access. This mapping is provided through use of a mapping table. This table can be
populated by any of the following three methods: static mapping, real-time DNS query, or
pre-fetched DNS query.
Populating the NAT46 mapping table
As described, NAT46 uses a mapping table to match the IPv4 destination address defined for an
IPv6 service with the actual IPv6 destination address of the service. This table is generated by one
of the following methods:
Static Mapping – You can manually configure the NAT46 gateway to contain an entry in the
mapping table to translate an IPv4 destination address to an IPv6 destination address. These
mappings are defined using the nat64 map command.