Networking & HTTP·Networking from DNS to production

TCP and UDP

Know when you need reliability and when you need low latency.

Beginner 12 min read Lesson 3 of 300 Challenge included

What you will be able to do

TCP guarantees order and delivery.
UDP is used for DNS, video and QUIC.
Ports identify services on both protocols.
Connection reuse reduces handshake cost.

In plain English

TCP provides ordered, reliable delivery with congestion control, at the cost of handshakes and retransmissions. UDP is connectionless and fast, leaving reliability to the application. HTTP/3 uses QUIC over UDP.

terminalTerminal

curl -v --http1.1 https://example.com/ 2>&1 | grep -E 'Connected|Reusing|HTTP/'
curl --http3 https://example.com/ -o /dev/null -sS -w '%{http_version}\n'

Your turn

Force HTTP/1.1

Easy

Write a curl command that forces HTTP/1.1 and shows headers.

BASH · starter

curl https://example.com

Check your understanding before moving on.

Knowledge checkQuestion 1

Which protocol guarantees ordered, reliable delivery?

Select an answer to continue

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Lesson 3 of 300 · 0% of course