Which feature is used to translate several internal addresses to only one or a few external
addresses (also referred to as “overload”)?
A.
Network Address Translation
B.
Address Translation Table
C.
Overload Address Method
D.
Port Address Translation
Explanation:
The PAT feature, a subset of NAT functionality, can be used to translate several internal
addresses into only one or a few external addresses. PAT uses unique source port numbers on
the private global IP address to distinguish between translations. Because the port number is
encoded in 16 bits, the total number could theoretically be as high as 65, 536 per IP address. PAT
will attempt to preserve the original source port number. If this number is already allocated then
PAT will attempt to find the first available port number starting from the beginning of the
appropriate port group 0–511, 512–1023, or 1024–655351. If there is still no port number available
from the appropriate group and more than one IP address is configured, PAT will move to the next
IP address in the pool and try to allocate the original source port number again. This continues
until it runs out of available ports and IP addresses.