Ages 15–17 · 10 levels · 3 free

Networks 2 for teens

Subnets, NAT, ports, TCP and UDP, and how an HTTPS connection is made. Pick subnet masks with a slider, trace a packet through NAT and an HTTPS connection, and finish by configuring a server firewall.

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1 Same Network? free ☆☆☆ 2 How Many Devices? free ☆☆☆ 3 Two Departments free ☆☆☆ 🔒 A Link Between Two Routers ☆☆☆ 🔒 Private and Public Addresses ☆☆☆ 🔒 NAT: Address Translation ☆☆☆ 🔒 Ports and Services ☆☆☆ 🔒 TCP or UDP? ☆☆☆ 🔒 How an HTTPS Connection Is Made ☆☆☆ 🔒 Final Mission: the Server Firewall ☆☆☆

Unlock all 10 levels

Levels 1–3 are free for everyone. Teachers and parents can unlock all levels with a plan, or try everything free for 30 days.

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What will you learn?

What a prefix like /24 and a subnet mask mean, how to work out how many devices fit in a subnet, how to split a network in two, when to use /30, which addresses are private and how NAT works, what ports are (22, 53, 80, 443 …), when TCP and when UDP is used, how an HTTPS connection is made with a certificate and how to configure a server firewall.