TOPIC / CATEGORY
Notes in Web & Networking
8 articles
Inspect a TLS Certificate with OpenSSL
Check the certificate a server actually presents, including names, issuer, validity, and chain details.
Troubleshooting Google Public CA and acme.sh
Work through Google Public CA problems with acme.sh, from EAB registration and DNS-01 validation to installation and renewal.
Nginx Location Matching in the Order That Matters
Predict which Nginx location block will handle a request by learning how exact, prefix, and regex matches are chosen.
A Small HTTP Header Check with curl
Inspect the headers a real GET request receives, follow redirects deliberately, and keep response bodies out of the terminal.
Measure an HTTP Request with curl Without Guessing
Find out which part of a slow HTTP request is slow, from DNS and TLS to the server's first byte, using curl's timing variables.
Test Nginx Configuration Before Reloading
Use Nginx's configuration test, inspect included files, and reload without replacing healthy workers with a broken configuration.
Google Trust Services Certificates with acme.sh: A 2026 Guide
Issue and renew a Google Trust Services certificate with acme.sh, Google Public CA EAB credentials, and a scoped Cloudflare DNS token.
Check DNS With dig Before Changing It
When a DNS change shows up in some places but not others, a few dig queries reveal which layer still has the old answer.