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Retrieving a smartphone's current location in the browser and displaying it on a map: Running the Geolocation API + Leaflet

Pass the latitude and longitude obtained via the Geolocation API to Leaflet to display the current position on the map. Observe the division of roles between location acquisition and map rendering.

2026.09.09

Programming / Web Development

Are JWTs encrypted? — Reading the structure without real tokens in PowerShell

Create a complete dummy JWT-like dataset in PowerShell and safely observe header.payload.signature and Base64URL decoding.

2026.09.09

Microsoft 365 / Azure

Trying IPv6 Communication with PowerShell — How is the localhost TCP of ::1 Different from IPv4?

Set up a TCP server and client on a single PC using the IPv6 loopback ::1, and observe the differences in endpoints and AddressFamilies.

2026.09.09

Networking / RFC

Calling WinRT Directly from PowerShell: Observing Windows Power States with PowerManager

A minimal smoke test to call WinRT's PowerManager directly from Windows PowerShell 5.1 and read remaining battery capacity and power supply status.

2026.09.09

PowerShell

Checking “Who is listening on this port?” in Ubuntu — Linking sockets and processes with ss

Learn how to check TCP listening ports and their associated processes in Ubuntu using ss. We also break down how to read 127.0.0.1, 0.0.0.0, and [::], and how permissions affect process displays.

2026.09.08

Linux / CLI / DevOps

Where Do SPF, DKIM, and DMARC Apply? — Understanding All Three Through the Flow of a Single Email

We break down the roles of SPF, DKIM, and DMARC through the lifecycle of a single email. Based on the 2026 DMARC standard RFC 9989, we also review differences from the older RFC 7489.

2026.09.08

Microsoft 365 / Azure

Dictionary is Convenient for Counting Duplicates in VBA — Aggregate Securely Without References

Use Scripting.Dictionary with Late Binding to aggregate duplicate values in column A. Output results to a dedicated sheet to prevent accidental deletion of input data.

2026.09.08

VBA / Office

In Which Layer Do HTTP 404, 502, and 504 Occur? — Troubleshooting from the Nginx and Application Request Path

Review the HTTP meanings of 404, 502, and 504 based on RFC 9110, and organize where to start investigating across Nginx and upstream applications along the request path.

2026.09.08

Networking / RFC

What to Check Before Changing Nginx Configuration? — Using nginx -t and nginx -T Properly

This article outlines a safe sequence for testing configurations with nginx -t before reloading Nginx, and using nginx -T to inspect the entire loaded configuration only when necessary.

2026.09.08

Linux / CLI / DevOps

Bulk Delete Empty Rows in Excel — Safely Cleaning Only the Target Table with Office Scripts

Using Office Scripts to delete only completely empty rows in a specified Excel table from the bottom up. When multiple tables exist, the target name must be specified to make it harder to accidentally modify other tables.

2026.09.08

VBA / Office