Interview Q&A / Computer Networks
Computer Networks interview questions
What happens when you open a website, TCP vs UDP, DNS and HTTP.
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- What are unicast, broadcast and multicast, and why can TCP not use the last two?
Unicast sends to one receiver, broadcast to every host on the local network, and multicast to a group that has joined. TCP needs a two-way connection with one peer, so it only supports unicast; broadcast and multicast use UDP.
IntermediateQuick answer1 min read - Why does DNS mostly use UDP, and when does it switch to TCP?
A DNS lookup is one small question and one small answer, so UDP avoids the cost of a handshake. DNS falls back to TCP when the answer is too large for a UDP response (truncated flag set), for zone transfers, and for DNS over TLS.
IntermediateQuick answer1 min read