Technical data

36 ServerIron ADX NAT64 Configuration Guide
53-1002444-02
Stateless NAT64 dynamic mapping configuration
3
DRAFT: BROCADE CONFIDENTIAL
• If the ipv6 frag-full-4to6 command is configured, the packet will be split and no further actions
will be performed.
• If the condition in step 1 is not met, and the DF bit is set at the server, the “fragmentation
needed” ICMP error message will be sent.
• If the conditions in steps 1 and 2 are not met, the packet will be split.
The ipv6 frag-full-4to6 command is configured as shown in the following example.
ServerIronADX(config)# ipv6 frag-full-4to6
Syntax: [no] ipv6 frag-full-4to6
For more information about NAT64 fragmentation support, refer to “NAT64 fragmentation support”
on page 5.
NOTE
The ipv6-frag-full-4to6 command was introduced in ServerIron ADX release 12.4.00 and it replaces
the frag-664-reverse-full-sized-pkt command from earlier releases.
Stateless NAT64 dynamic mapping configuration
The stateless NAT64 gateway uses a mapping table to translate the IPv6 addresses to IPv4
addresses and vice versa. This mapping table can be configured manually (using static mapping)
or generated dynamically (using real-time dynamic learning or prefetched dynamic learning).
Dynamically generated mapping tables can be populated in real time by way of real-time dynamic
learning or pre-populated by way of prefetched dynamic learning. You must configure a DNS server
IP address on the ServerIron ADX to use dynamic mapping.
• Real-time dynamic learning: If a packet is received at the NAT64 gateway with an IPv6
destination address within the range defined by the NAT64 IPv6 prefix and it does not contain
an entry in its mapping table for that IPv6 address, the gateway will send an IPv6 pointer (PTR)
query to the DNS server to obtain the host name of the resource it is trying to reach. The
NAT64 gateway then sends a query for the host name to determine the corresponding IPv4
address. The mapping defined by this operation is then entered into the mapping table of the
NAT64 gateway.
• Prefetched dynamic learning: The NAT64 gateway can be configured to periodically send IPv6
PTR queries to the DNS server to identify IPv4 address translations for each of the IPv6
destination addresses defined within the IPv6 prefix subnet. The NAT64 gateway uses this
information to populate its mapping table.
NAT64 real-time dynamic mapping configuration
The tasks required to configure a ServerIron ADX for NAT64 translation using mapping tables that
are dynamically generated in real time include the following:
• “Configuring NAT64 IPv6 prefixes with real-time dynamic learning” on page 37
• “Configuring NAT64 IPv4 prefixes with real-time dynamic learning” on page 37
• “Configuring NAT64 with real-time dynamic learning” on page 37