What does DNS do?
ARoutes datagrams between subnets
BTranslates domain names to IP addresses
CDetects packet corruption
DEstablishes encrypted sessions
Answer & Solution
Correct answer: B. Translates domain names to IP addresses
1. DNS (Domain Name System): translates domain names like `example.com` to IP addresses like `93.184.216.34` (and vice versa).
2. STRUCTURE: distributed hierarchical database. Root → TLD (.com, .org) → Domain (.example) → Subdomain.
3. DEFAULT port: 53 (both UDP and TCP).
4. Without DNS, users would have to remember IP addresses for every site they visit.
5. Options A, C, D describe other protocols (IP, checksum, TLS).
_Source: RFC 1180 "A TCP/IP Tutorial", §8 (Network Applications) + RFC 1034/1035._
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