Build a Firewall (Packet Filter)
Build an iptables-style firewall: stateless and stateful packet filtering, connection tracking, NAT/SNAT/DNAT, port forwarding, rate limiting (token bucket), routing/forwarding, logging/monitoring, and the design behind Linux netfilter, BSD pf, and cloud security groups.
advanced10 lessons4 chapters10 graded exercisesPython
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What you’ll have built
Chapter by chapter. Every step is a graded exercise.
- Packet Filtering Basics
- Stateful Inspection
- NAT & Forwarding
- Production
Starts in Python — solve in the language you choose in the editor, same tests either way.
Curriculum
4 chapters, 10 lessons. Each lesson is a short read, one graded exercise, and a quiz.
- 1What Firewalls SolveRead · exercise · quiz
- 2Rules & ActionsRead · exercise · quiz
- 3Ports & ProtocolsRead · exercise · quiz
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