Technical data

6 ServerIron ADX NAT64 Configuration Guide

53-1002288-02

NAT64 Connection logging

DRAFT: BROCADE CONFIDENTIAL

• populates the fragment ID, offset, and flags of the IPv4 header

For the IPv4 to IPv6 direction, ADX:

• extracts information stored in the IPv4 header

• creates and populates the IPv6 fragment header

NOTE

Because the nature of the ICMP checksum mechanism in IPv6 is different than in IPv4, ICMP

fragmentation is currently not supported, and all fragmented ICMP packets received on either IPv6

or IPv4 will be dropped. There are counters that keep track of the number of packets dropped.

NOTE

When a IPv4 host sends multiple fragments with UDP checksum 0, the translation of those packets

from IPv4 to IPv6 is not supported

When installing NAT64 on a ServerIron ADX with a previous config

If a ServerIron ADX was previously configured with any "server ...." configuration statements for

SLB, they must be removed prior to creating any NAT64 configuration and the device must be

rebooted.

This can be done by either of the following methods:

Option 1: Manually prepend a "no " keyword in front of each complete "server " statement, thus

removing each configuration statement or section in a granular fashion. Write the config to

memory and then reload.

Option 2: Completely erase the entire configuration with the erase startup-config command and

then reload without saving.

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NAT64 Connection logging

A ServerIron ADX provides NAT64 connection logging to enable administrators to audit and log

NAT64 connections created on the ServerIron ADX. A user can configure the ServerIron ADX to send

a message to an external Syslog server each time NAT64 creates session table entries for NAT64

traffic.

The forward flow for NAT64 is from the IPv6 Client to the NAT64 IPv6 prefix::ipv4 destination

address. The ServerIron ADX selects a NAT pool IP and port to replace the Client IP and strips off

the NAT64 prefix to create the IPv4 destination address.

The logging displays the addresses of the following:

• Protocol

• Client IP

• Client Port

• NAT64 prefix

• IPv4 destination IP

• Destination port