Technical data

ServerIron ADX NAT64 Configuration Guide 33
53-1002288-02
Configuring NAT64 for IPv4-only client to IPv6 resource
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DRAFT: BROCADE CONFIDENTIAL
Syntax: [no] nat64 ipv6-prefix <prefix/subnet> [inject-static-route { ve <port-number> | ethernet
<port-number> ] stateless
The <prefix/subnet> variable specifies the NAT64 IPv6 prefix that will be used by the ServerIron
ADX when operating as a NAT46 gateway.
The inject-static-route option is used to advertise the subnet defined by the <prefix/subnet>
variable on the IPv6 network. It is configured for an IPv6 interface specified by the ve
<port-number> or ethernet <port-number> variable. It should be the interface connected to the
adjacent router. NAT46 route injection is described in detail in “Route injection NAT46” on page 35.
Configuring static mapping
You can populate the mapping table of the NAT46 gateway statically by configuring a nat64 map
command that identifies an IPv4 address within the subnet defined by the NAT64 IPv4 prefix and
maps it to the IPv6 address of a resource. This mapping is performed as shown.
ServerIron ADX(config) nat64 map 201.1.1.100 2001:db7:8000::100
Syntax: [no] nat64 map <IPv4-address> <IPv6-address>
The <IPv4-address> variable defines an IPv4 address within the subnet defined by the NAT64 IPv4
prefix that identifies an IPv6 resource to the IPv4 only network.
The <IPv6-address> variable specifies the IPv6 address of the IPv6 resource that is being mapped
to the IPv4 address specified by the <IPv4-address> variable within this command.
Configuring DNS dynamic learning
You can configure a ServerIron ADX to perform dynamic learning of IPv4 to IPv6 mappings through
DNS as shown.
ServerIron ADX(config) nat64 dns-dynamic-learning
Syntax: [no] nat64 dns-dynamic-learning
With this command configured a ServerIron ADX will discover IPv6 to IPv4 mappings through DNS
whenever the DNS server receives a new IPv4 destination or IPv6 source. With this command
configured, you can configure a ServerIron ADX to prefetch mappings for IPv4 prefixes using the
nat64 ipv4-prefix <prefix/subnet> prefetch command.
You can clear all entries created using dynamic learning as described in “Clearing IPv6-IPv4
mappings learned through DNS” on page 40.
Configuring a back-off interval for DNS discoveries
A DNS discovery (or refresh) fails if three retries time-out or the DNS64 server returns an error. In
this situation the NAT46 gateway may still receive traffic intended for IPv6 resources. Instead of
retrying a request to the DNS64 server immediately, you can configure a ServerIron ADX to wait for
a period of time. This is configured as shown.
ServerIron ADX(config) nat64 dns-fail-holdoff 300
Syntax: [no] nat64 dns-fail-holdoff <holdoff-interval>
The <holdoff-interval> variable is configured in seconds. The default value is 180 seconds.
Configurable values are 10 to 3600 seconds.