Beginner · Lessons: 4
TCP/IP: addresses, ports and connections
The rules every device on the internet follows: IP addresses, ports, TCP and UDP, and what your router does.
- 1 IP addresses: IPv4, IPv6, public and private
What an IP address actually is, why the internet uses two different formats, and why your laptop’s own address is not the one strangers see.
6 min - 2 Ports, TCP and UDP
Why one IP address can run a hundred conversations at once, and why some of those conversations trade speed for reliability.
7 min - 3 The TCP handshake and a connection’s life
How two computers agree to talk before either sends real data, how they end the conversation, and what a firewall watching in the middle actually sees.
7 min - 4 Your router and NAT
Why every device in your home can be online at once through a single public address, and what that arrangement does and does not protect you from.
6 min
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