ITPEC FE Morning April 2023 Question 31

Mapping domain and host names to IP addresses — DNS is the Internet's distributed directory of names.

When a program uses a name such as www.example.com, the resolver asks a DNS server, which answers with the address from its resource records (A for IPv4, AAAA for IPv6). DNS also does reverse lookup, from an address to a name, and its MX records name the mail servers of a domain.

Answer (c)

Why not others:

• •(a) — translating a private IP address into a global one for Internet access is NAT (or NAPT).
• •(b) — DNS only returns an address for a name; it does not locate or invoke programs on a server, which is the job of remote procedure call middleware.
• •(d) — handing out an unused address from a registered pool on request is DHCP.

Key rule: DNS turns names into IP addresses, ARP turns IP addresses into MAC addresses, DHCP assigns addresses, and NAT translates private addresses to global ones.

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