Question

Which of the following statement(s) is/are true about NAT/PAT?

a.PAT is also called as NAT overload

 

b.NAT is also called as PAT overload

 

c.NAT technology prevents IPV4 address depletion

 

d.PAT can map multiple private IPV4 addresses to single public IP addresses

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Answer 1

Answer:

A. PAT is also called as NAT overload

Explanation:

I don't know about others.

Answer 2

Answer:

a. PAT is also called as NAT overload.

Explanation:

NAT Overloading or Port Address Translation (PAT) is a modified form of dynamic NAT where the number of inside local addresses is greater than the number of inside global addresses. Most of the time, all inside hosts have access to the Internet via a single inside global IP address. The only type of NAT that actually saves IP addresses is NAT Overloading, which is also the most widely used type of NAT.

• PAT permits overloading, which is the mapping of multiple inside local addresses to a single inside global address. However, this also implies that when return packets reach the NAT router, they will all have the same destination address.
• The NAT entries in the translation table are extended entries to deal with this scenario; the entries track not only the pertinent IP addresses but also the protocol types and ports. Up to $65535$ inside local addresses could theoretically be mapped to a single inside global address by translating both the IP address and the port number of a packet (based on the $16-$bit port number).
• However, keep in mind that each NAT entry takes up about $160$ bytes of router memory, which means that $65535$ entries would require more than $10$ MB of memory as well as a significant amount of CPU power. Although this number is far from being mapped in actual PAT configurations, it is unquestionably a theoretical cap.