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Networking

DNS, HTTP, TLS, and the diagnostic tools you reach for when something on the wire is broken.

Hands-on labsbeginner26 labs
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Linux

You can still start this course now. Earlier courses give you the mental model the labs here assume.

By the end you'll be able to
  • Trace a request from your laptop to the server and back
  • Diagnose DNS, TLS, and HTTP failures one layer at a time
  • Read a curl -v dump and know what each line means
  • Stand up a reverse proxy without copy-pasting nginx configs

Modules

Work through the labs in order. Each module builds one operating habit.

  1. 01
    IPv4 and IPv6 addresses on this host
    Every machine on a network is identified by one or more IP addresses. Read the addresses on this sandbox, see the IPv4 and IPv6 forms, and notice the loopback address every host has.
    10 min
    Start
  2. 02
    Ports, sockets, and well-known services
    An IP address identifies a host. A port identifies which program on that host. A socket is the IP plus port pair. See the well-known port list and confirm common services.
    12 min
    Start
  3. 03
    ping and traceroute for reachability
    ping asks one question, is the host alive. traceroute answers a second, which routers does my packet pass through. Use both to debug a slow or broken connection.
    10 min
    Start