Primers

No primers match.

1. 01
   The OSI model

   Networking The seven layers networking gets described in, the four-layer model the internet actually uses, what happens to one request on its way down and back up, and how to use the layers to troubleshoot.

2. 02
   IP addresses and CIDR

   Networking An IPv4 address is one 32-bit number, and the /n in CIDR notation says how many of those bits are locked.

3. 03
   AWS VPCs, subnets, and routing

   Networking How a VPC is carved into subnets, how route tables make a subnet public or private, how security groups and network ACLs filter traffic, and how to lay it all out.

4. 04
   How DNS resolution works

   Networking The steps between typing a name and connecting to an address, who answers each question along the way, why changes take time to show up, and where Route 53 fits.

5. 05
   Load balancers and TLS termination

   Networking Layer 4 vs. layer 7, NLBs vs. ALBs, what it means to terminate TLS, and how to put HTTPS in front of a single server without a load balancer at all.

6. 06
   Certificates and Trust

   Networking What a TLS certificate is, how keys and signatures make it trustworthy, what root, intermediate, and leaf certificates are for, how you get one, and what to do when a client refuses to trust it.

7. 07
   Giving a machine a name you control

   Networking A hosts-file line or an SSH config alias can point a name at a machine without touching DNS. How each works, which to use, and how to tell a naming problem from a network one.

8. 08
   The TLS handshake

   Networking The first few messages of every HTTPS connection, where the browser checks who it's talking to and the two sides agree on a secret key in public, plus what's different in TLS 1.2, what someone watching can still see, and how to watch it happen.

9. 09
   Reaching private resources

   Networking The ways into a private network, from connecting whole networks with VPNs and Transit Gateway to forwarding one port for an afternoon, and what to check when you're connected but still can't reach anything.

10. 10
    Network file shares

    Networking How machines share folders over a network with SMB and NFS, how a NAS differs from a SAN or a local disk, which ports each one needs and which way the connections go, and why port 445 never belongs on the internet.

11. 01
    Kubernetes object size limits

    Kubernetes Why a ConfigMap, a Secret, or a Helm release record fails with "Too long: may not be more than 1048576 bytes", where the 1 MiB cap comes from, and how to get under it.

12. 02
    Why a pod keeps restarting

    Kubernetes Telling the causes of a restart apart from the exit code, why an app that looks healthy can still fail its liveness probe, and the order to check things in.

13. 01
    Java heap size and container memory

    Java What the JVM heap is, how its default maximum is chosen inside a container, why it is only a quarter of the limit, how that plays out in a container, a pod, or on a server, how to read the value a running service uses, and which garbage collector a small container gets.

14. 01
    Deploying to an on-prem Windows server

    Deployment Three ways to run an installer or an Ansible playbook on a Windows server outside AWS (CodeDeploy, Ansible over WinRM, and Systems Manager), and which direction the network connection goes in each.

15. 02
    GitOps, Argo CD and Flux

    Deployment What GitOps means, how a commit in git turns into a change in a Kubernetes cluster, and how Argo CD and Flux differ in doing it.

16. 01
    The Presocratics

    Philosophy The first Greek philosophers, from Thales to the atomists, the two questions they kept asking (what is everything made of, and how can anything change), and how each answer set up the next.

17. 02
    The Sophists and Socrates

    Philosophy How philosophy turned from nature to people in 5th-century Athens, the paid teachers of argument who said truth depends on who's judging, and the man who spent his life asking people what they meant by "good."

18. 03
    Plato

    Philosophy Socrates' student, the writer who turned him into a character so nobody would forget him, his best-known ideas (the ladder of love, the allegory of the cave, and the world of Forms), and the ideal city of the Republic, with philosopher kings at the top and tyranny at the bottom.

19. 01
    The original language of the New Testament

    Theology Why the New Testament was written in Greek when Jesus taught in Aramaic, the Aramaic words that survive in it, what the oldest manuscripts show, and where the claim of an Aramaic original comes from.

20. 01
    Reviewing code with an AI, against a ticket

    Working with AI How to set up an AI code review so it checks the change against the ticket's requirements, then for security, then for code health, adds reliability and infrastructure passes when a change needs them, and why it should run the code instead of only reading it.

21. 02
    Running an MCP server locally over stdio

    Working with AI How an AI client starts an MCP server as a child process and talks to it through standard input and output, how to register one, and how to test changes to it before anyone else depends on it.

22. 03
    RAG, and keeping it fed from shared notes

    Working with AI What retrieval-augmented generation is and how one question flows through it, how the search finds the right notes, and how to keep the index up to date automatically from a shared notes folder without leaking notes people shouldn't see.