Module 5: Network Protocols & Sockets: Mistake Clinic

This clinic turns wrong moves into reusable judgment. Use it after each practice page and again before the quiz or checkpoint.

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Module-Specific Mistake Radar

Start with these traps. Replace or extend them with real mistakes from your own work.

Mistake to look for	Where it shows up	Symptom	Repair evidence
Finishing Layered Model and Addressing Lab with only a final answer	Layered Model and Addressing Lab	The work has no failed case, trace, test, proof gap, or design stress point.	Add the smallest broken example and show the repair that changes the result.
Finishing Transport and Connection Clinic with only a final answer	Transport and Connection Clinic	The work has no failed case, trace, test, proof gap, or design stress point.	Add the smallest broken example and show the repair that changes the result.
Finishing HTTP, TLS, and Application Workshop with only a final answer	HTTP, TLS, and Application Workshop	The work has no failed case, trace, test, proof gap, or design stress point.	Add the smallest broken example and show the repair that changes the result.
Finishing Code Katas with only a final answer	Code Katas	The work has no failed case, trace, test, proof gap, or design stress point.	Add the smallest broken example and show the repair that changes the result.
Treating The Layered Model: Physical, Link, Network, Transport, Application as vocabulary instead of a tool	The Layered Model: Physical, Link, Network, Transport, Application	The explanation names the concept but cannot decide between two cases.	Write one example, one non-example, and the rule that separates them.
Treating Encapsulation: Headers, Payloads, and Protocol Stacks as vocabulary instead of a tool	Encapsulation: Headers, Payloads, and Protocol Stacks	The explanation names the concept but cannot decide between two cases.	Write one example, one non-example, and the rule that separates them.

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Practice Mistake Checks

Pull any miss from these checks into your mistake log.

Layered Model and Addressing Lab

Source: practice/01-layered-model-and-addressing-lab.md

For each statement, identify the error:

1. "My MAC address identifies my laptop on the Internet."
2. "10.0.24.53/20 includes 10.0.33.10, because they start the same way."
3. "NAT is a firewall."
4. "DNS resolution happens in the kernel, like TCP does."
5. "Encapsulation adds headers only at the transport layer."

Transport and Connection Clinic

Source: practice/02-transport-and-connection-clinic.md

For each statement, identify the error:

1. "UDP is unreliable, so it is for toy apps."
2. "TCP makes all packets arrive in the order they were sent."
3. "The sender's congestion window and the receiver's advertised window are the same thing."
4. "CLOSE_WAIT means the kernel is closing the socket."
5. "Retransmissions only happen on timeout."

HTTP, TLS, and Application Workshop

Source: practice/03-http-tls-and-application-workshop.md

For each statement, identify the error:

1. "HTTPS encrypts the URL."
2. "HTTP/2 eliminates head-of-line blocking entirely."
3. "A 500 means the user did something wrong."
4. "PUT and POST are interchangeable."
5. "TLS is just encryption -- authentication is a separate feature."

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Repair Protocol

For each real mistake:

1. Reproduce the failure on the smallest example, trace, proof, query, command, or design sketch.
2. Name the hidden assumption.
3. Repair the artifact.
4. Save evidence that changed: failing then passing test, corrected proof step, revised diagram, safer command, benchmark, or review note.
5. Add one retrieval card beginning with Check... before... or Do not use... when....

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Mistake Log

Date	Mistake	Symptom	Root cause	Repair evidence	Retrieval card
Starter	Pick one radar row above	Explain how it would fail in this module	Name the assumption	Add a counterexample or corrected artifact	Write the card before closing the page

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Completion Standard

• At least five real mistakes are logged.
• At least two mistakes include a counterexample or failing test.
• At least one mistake connects to an older semester skill.
• At least one correction changes code, a proof, a diagram, a command transcript, a query, or a design decision.