World 4 · What Happens When You Type a URL · 11 min · PRO
Names instead of numbers
The DNS idea
PRO · How the Internet Works
World 4: What Happens When You Type a URL is part of PRO
The first world of How the Internet Works is free. PRO opens the other 26 lessons in 6 worlds — simulations, quizzes and all.
PRO includes
- All 60 labs — every world, every lesson
- Practice exams and certificates
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