The firewall supports translation for /32, /40, /48, /56, /64,
and /96 subnets using these prefixes. A single firewall supports
multiple prefixes; each NAT64 rule uses one prefix. The prefix can
be the Well-Known Prefix (64:FF9B::/96) or a Network-Specific Prefix
(NSP) that is unique to the organization that controls the address translator
(the DNS64 device). An NSP is usually a network within the organization’s
IPv6 prefix. The DNS64 device typically sets the u field and suffix
to zeros; the firewall ignores those fields.