Technical data

ServerIron ADX NAT64 Configuration Guide 31

53-1002288-02

Operation of NAT46 for IPv4-only client to IPv6 resource

DRAFT: BROCADE CONFIDENTIAL

FIGURE 10 IPv6 client to DNS server communication

The request packet is then sent with the IPv4 source address of the client (192.0.2.1) to the

destination IPv4 address that was obtained for “brocadetest.com” (100.1.1.1) from the DNS64

server. The packet destined for “brocadetest.com” arrives at the NAT46 gateway with a destination

address of “100.1.1.1”. The NAT46 gateway then uses its mapping table to translate the

destination address into the IPv6 address of the IPv6-only server that hosts “brocadetest.com”.

The mapping table used for this translation is populated as described in “Populating the NAT46

mapping table” on page 29. In this example, the IPv6-only resource has an IPv6 address of

2001:11::.

The NAT46 gateway then uses the IPv6-prefix with the IPv4 address that the client used to reach

the IPv6 resource to create a source address for the packet being forwarded to the IPv6-only

resource. In this example, the IPv6-prefix (2001:db8) is combined with the IPv4 address of the IPv6

resource (100.1.1.1) to create the IPv6 source address “2001:db8 100.1.1.1” for the packet being

forwarded to the IPv6 resource.

When the IPv6-only resource sends a return packet to the IPv4-only client, the NAT46 gateway

strips out the IPv6 portion of the destination address and uses the IPv4 portion for the source

address. The gateway then maps the correct IPv4 destination address as determined from its

mapping table. The process occurs as shown in Figure 11.

FIGURE 11 Stateless NAT46 translation

DNS 64 Server

IPv4 Client

IPv4

www.brocadetest.com

100.1.1.1

DNS 64 Server

Stateless NAT46 translation

IPv4-only Client

IPv4 address = 192.0.2.1

IPv6-only Server

IPv6 address = 2001:11::

ServerIron ADX

with NAT46

Source IP = 192.0.2.1

Destination IP = 100.1.1.1

Source IP = 2001:db8::100.1.1.1

Destination IP = 2001:11::

Source IP = 100.1.1.1

Destination IP = 192.0.2.1

Source IP = 2001:11::

Destination IP = 2001:db8::100.1.1.1