Which two statements about NAT444 are true? (Choose two.)

A.
NAT444 packets are translated three times.

B.
NAT packets traverse three IPv4 addressing domains.

C.
NAT444 needs to work together with DNS64.

D.
There are two types of NAT444 (stateful or stateless).

E.
NAT is performed by the CPE and also by the service provider router.

Explanation:
Carrier-grade NAT (CGN), also known as large-scale NAT (LSN), is an approach to IPv4 network
design in which end sites, in particular residential networks, are configured with private network
addresses that are translated to public IPv4 addresses by middlebox network address translator
devices embedded in the network operator’s network, permitting the sharing of small pools of
public addresses among many end sites. This shifts the NAT function and configuration thereof
from the customer premises to the Internet service provider network.
Carrier-grade NAT has been proposed as an approach for mitigating IPv4 address exhaustion.[1]
Critics of carrier-grade NAT argue the following aspects:
Like any form of NAT, it breaks the end-to-end principle.[2]
It has significant security, scalability, and reliability problems, by virtue of being stateful.
It makes record keeping for law-enforcement operations more difficult.

It makes it impossible to host services on well known ports.
It does not solve the IPv4 address exhaustion problem when a routable IP address is needed,
such as in web hosting.
One use scenario of CGN can be described as NAT444,[3] because some customer’s connections
to public servers would pass through three different IPv4 addressing domains: the customer’s own
private network, the carrier’s private network, and the public Internet.
Another CGN scenario is Dual-Stack Lite, in which the carrier’s network uses IPv6 and thus only
two IPv4 addressing domains are needed.