Technical data

ServerIron ADX NAT64 Configuration Guide 35
53-1002288-02
Route injection NAT46
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DRAFT: BROCADE CONFIDENTIAL
Changing the DNS back-off interval
To change the back-off interval for DNS discovery (during which the ServerIron ADX does not try to
re-query the DNS server for mapping that recently generated a failure) use the following
commands.
ServerIron ADX(config) nat64 dns-fail-holdoff 300
Pre-fetching IP mappings from the DNS server
To pre-fetch all of the available mappings for the IPv4 subnet defined by the IPv4 prefix, use the
prefetch option as shown.
ServerIron ADX(config) nat64 ipv4-prefix 100.1.1.0/24 prefetch
Configuring a static mapping
You can configure a static mapping between an IPv4 address and an IPv6 address as shown.
ServerIron ADX(config) nat64 map 100.1.1.1 /32 2001:db8:fff:32
To delete a static mapping, just use the command with the no option as shown.
ServerIron ADX(config) no nat64 map 100.1.1.1 /32 2001:db8:fff:32
Route injection NAT46
As described previously, IPv4 addresses are defined on the ServerIron ADX to represent IPv6
resources to IPv4 clients. This is done by defining an IPv4 prefix for an IPv4 subnet where the IPv4
addresses can reside. Also, an IPv6 prefix for an IPv6 subnet is defined on the ServerIron ADX to
represent IPv4 clients to the IPv6 resources. The addresses assigned for these translations need to
be made available as destinations in the routing tables of the IPv6 and IPv4 networks that they
reside in. For this reason, we provide command options that direct the ServerIron ADX to inject
routes to these addresses into respective networks routing tables. Route distribution is then
performed using any of the routing protocols supported by the ServerIron ADX: OSFP, IS-IS and BGP
(IPv4 and IPv6).
NAT46 route injection requires that the ServerIron ADX have a routing adjacency relationship with a
router for the protocols you want to support route distribution with. For resources that are mapped
to an IPv4 address, the IPv4 subnet is defined by the IPv4 prefix specified with the nat64
ipv4-prefix command. This command has the inject-static-route option which directs the ServerIron
ADX to inject a static route to each of the IPv4 addresses within the defined IPv4 subnet that have
an IPv6 address mapped to them. This mapping can be either performed using DNS dynamic
mapping or though creation of a static entry using the nat64 map command. This destination is
advertised to the adjacent neighbor and made available in routing tables of the IPv4 network.
For resources that are mapped to a subnet defined by the IPv6 prefix, the nat64 ipv6-prefix
command has an option to identify an interface on the ServerIron ADX (Ethernet or VE) as the
destination for the IPv6 subnet. The interface configured with this command must have an IPv6
address assigned to it.