Knowledge Base

Step-by-step manual troubleshooting guides — no scripts, just the exact commands a human types by hand. Organized by support level (Level 1-3) and severity, so it works whether you're a student, a support tech, or a manager reviewing a live issue.

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How to Read Your Diagnostic Report

Start here: what health scores, severity levels, and PASS/WARNING/FAIL mean, and which guide to read next.

Read the orientation guide

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Getting Started

L1Informational

How to Read Your Diagnostic Report

Start here: what health scores, severity levels, and PASS/WARNING/FAIL mean, and which guide to read next.

No tools required

DNS Resolution

L1High

DNS Resolution: Why Won't This Domain Resolve?

A step-by-step manual walkthrough for diagnosing DNS resolution failures using nslookup, dig, and ping.

nslookup, dig (optional), ping5-10 minutes

Ports & Firewall

L1High

Ports & Firewall: Is Something Blocking the Connection?

How to manually check whether a specific port is open, and whether a firewall is the reason it isn't.

Test-NetConnection (PowerShell), telnet (optional), Windows Firewall

HTTP / Website Reachability

L1High

HTTP Reachability: Why Won't This Website Load?

Using curl and browser DevTools to see exactly what happens when a website is requested.

curl, browser DevTools

TLS / Certificate Validity

L2Critical

TLS & Certificates: Is the HTTPS Certificate Valid?

Using openssl to inspect a certificate's chain, expiry date, and hostname match by hand.

openssl

Security Headers

L2Medium

Security Headers: What Is This Site Actually Protecting Against?

Using curl and browser DevTools to check for HSTS, CSP, and other security headers.

curl

Cookie Security

L2Medium

Cookie Security: Are Cookies Configured Safely?

Using browser DevTools to check whether cookies have the Secure, HttpOnly, and SameSite attributes set.

browser DevTools

Cache & CDN Behavior

L2Low

Cache & CDN: Am I Seeing an Old Cached Version?

Using curl and DevTools to tell whether a response was served from cache and by what.

curl

Performance

L2Medium

Performance: Which Phase Is Actually Slow?

Using browser DevTools and curl's timing output to isolate whether DNS, connection, TLS, or the server itself is the bottleneck.

browser DevTools, curl

Local Machine Fixes

L1Low

Local Machine Fixes: Clearing DNS Cache, Firewall, and Network Services

The standard set of local fixes to try on your own machine before escalating a network issue.

ipconfig, netsh, services.msc

Ping & Packet Loss

L1High

Ping & Packet Loss: Is the Network Path Dropping Traffic?

Using ping and tracert to measure latency and packet loss, and to localize where loss is happening.

ping, tracert

Certificate / PFX Management

L3Critical

Certificate & PFX Management: Validating and Bundling a Certificate

Manually verifying a certificate matches its private key and building a PFX bundle with openssl.

openssl, certutil (Windows)

VLAN & Switch Troubleshooting

L3Critical

VLAN & Switch Troubleshooting: Tracing a Connectivity Issue Over SSH

Using standard Dell OS10 show commands over SSH to trace a VLAN/interface/switch-level issue.

SSH client, switch CLI access