ITPEC IP October 2024 Question 30
Which of the following is the appropriate combination of terms or phrases to be inserted into blanks A and B in the description below concerning NAT?
NAT is often used when an office or a household LAN is connected to the Internet, and it converts between A and B.
Explanation
A: private IP addresses, B: a global IP address — NAT translates between the addresses used inside a LAN and the one used on the Internet.
PCs in an office or home use private IP addresses, which are not routed on the Internet. When a packet leaves, the router running NAT (Network Address Translation) replaces the private source address with its global IP address, and on the way back it restores the private address. This lets many PCs share one global address.
Answer (b)
Why not others:
- •(a) — a MAC address identifies a network interface within a local link; NAT does not convert IP addresses into MAC addresses (that lookup is ARP)
- •(c) and (d) — converting host names to IP addresses is the job of DNS, not NAT
Key rule: NAT maps private IP addresses to a global IP address; DNS maps names to IP addresses; ARP maps IP addresses to MAC addresses.
Networks · AI-written, may contain errors
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