Core · Networks Free to read
Computer Networks tutorial
Addresses, DNS, TCP, HTTP and the whole journey of a request, plus how to find what's broken.
Learn it by doing
The interactive course has the same lessons with an editor next to them: run every example, answer the quizzes and solve exercises that are checked the moment you submit. Free to start, no sign-up.
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1
IP addresses and subnetsHow does one computer find another among billions?2
DNSHow does a name like shop.example.com turn into an address?
Addresses and names
IP addresses, subnets and DNS.2
3
TCP, UDP and portsHow do two programs hold a reliable conversation over an unreliable network?4
HTTP requests and responsesWhat does a browser actually send to a web server?
Talking reliably
Ports, TCP and HTTP.3
5
Finding what's brokenThe site is down. Where do you start?6
From URL to pageWhat happens after you type a URL and press Enter?