Configuring Prefix-Based IPv6-IPv4 Translation

Prefix-based translation is a process of translating packets sent from private IPv6 servers into IPv4 packets, using an IPv6 prefix configured in the NetScaler appliance. This prefix has a length of 96 bits (128-32=96). The IPv6 servers embed the destination IP address of the IPv4 servers or hosts in the last 32 bits of the destination IP address field of the IPv6 packets. The first 96 bits of the destination IP address field are set as the IPv6 NAT prefix.

The NetScaler appliance compares the first 96 bits of the destination IP address of all the incoming IPv6 packets to the configured prefix. If there is a match, the NetScaler appliance generates an IPv4 packet and sets the destination IP address as the last 32 bits of the destination IP address of the matched IPv6 packet. IPv6 packets addressed to this prefix have to be routed to the NetScaler so that the IPv6-IPv4 translation is done by the NetScaler.

In the following diagram, 3ffe::/96 is configured as the IPv6 NAT prefix on NetScaler NS1. The IPv6 host sends an IPv6 packet with destination IP address 3ffe::74.125.91.105. NS1 compares the first 96 bits of the destination IP address of all the incoming IPv6 packets to the configured prefix, and they match. NS1 then generates an IPv4 packet and sets the destination IP address as 74.125.91.105.

Figure 1. IPv6-IPv4 Prefix-Based Translation

ipv4-6 prefix translation

To configure prefix-based IPv6-IPv4 translation by using the NetScaler command line:

At the command prompt, type:

  • set ipv6 [-natprefix <ipv6_addr *>]
  • show ipv6

Example:

> set ipv6 -natprefix 3ffe::/96
 Done

To configure prefix-based IPv6-IPv4 translation by using the NetScaler GUI:

Navigate to System > Network, in the Settings group, click Configure INAT Parameters, and set the Prefix parameter.

Configuring Prefix-Based IPv6-IPv4 Translation

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