| Exam 640-878 | Question id=4931 | Routed Network Technologies II |
Which two statements about NAT64 are true?
| A. |
NAT64 packets traverse two IPv4 addressing domains. | |
| B. |
NAT64 packets are translated two times. | |
| C. |
There are two types of NAT64 (stateful or stateless). | |
| D. |
NAT is performed by the CPE and also by the service provider edge router. | |
| E. |
The DNS64 server embeds the IPv4 address from the DNS A record with a preconfigured IPv6 translation prefix. |
All viable translation scenarios are supported by NAT64, and therefore NAT64 is becoming the most sought translation technology. AFT using NAT64 technology can be achieved by either stateless or stateful means:
* Stateless NAT64, defined in RFC 6145, is a translation mechanism for algorithmically mapping IPv6 addresses to IPv4 addresses, and IPv4 addresses to IPv6 addresses. Like NAT44, it does not maintain any bindings or session state while performing translation, and it supports both IPv6-initiated and IPv4-initiated communications.
* Stateful NAT64, defined in RFC 6146, is a stateful translation mechanism for translating IPv6 addresses to IPv4 addresses, and IPv4 addresses to IPv6 addresses. Like NAT44, it is called stateful because it creates or modifies bindings or session state while performing translation. It supports both IPv6-initiated and IPv4-initiated communications using static or manual mappings. DNS64, an optional component defined in RFC 6147, when used in conjunction with NAT64, would trick the IPv6 hosts into thinking that the IPv4 destination as an IPv6 address, by synthesizing AAAA (quad A) resource records from A resource records.