DomainOpsDomainOps Blog
Practical write-ups on domain monitoring, SSL hygiene, DNS security, and the day-to-day mechanics of keeping a portfolio of domains healthy.
The SSL Certificate Chain Explained
The SSL certificate chain explained: root, intermediate and leaf certs, why a site works in your browser but fails in curl, and how to debug an incomplete chain.
Bulk WHOIS Lookup: Auditing a Whole Domain Portfolio
A practical bulk WHOIS lookup guide: audit every domain's expiry and registrar at once, work around WHOIS/RDAP rate limits, and keep the data fresh.
Website Uptime Monitoring: A Practical Guide
A practical guide to website uptime monitoring: what to check, the right intervals, beating alert fatigue, and telling a brief blip apart from a real outage.
SPF, DKIM and DMARC: the complete guide and deploy order
How SPF, DKIM and DMARC fit together, the right order to deploy them, alignment explained, and a practical checklist to lock down email authentication.
How to Read a WHOIS Record: A Field-by-Field Guide
Learn how to read a WHOIS record field by field: registrar vs registrant, key dates, nameservers, and what status codes like clientHold and pendingDelete mean.
How to Check SSL Certificate Expiration (3 Ways)
How to check SSL certificate expiration with openssl one-liners, your browser, and automated monitoring — copy-paste commands and when to use each method.
How to find dangling DNS records before attackers do
Dangling DNS records point at cloud resources you no longer own. Learn what makes a record dangling across S3, GitHub Pages, Heroku and Azure, and how to detect them.
DMARC record guide: p=none, quarantine, reject and reports
A practical DMARC record guide: p=none vs quarantine vs reject, a safe rollout strategy, alignment, and how to actually read aggregate (RUA) reports.
What Happens When an SSL Certificate Expires?
What happens when an SSL certificate expired: browser warnings, broken APIs, lost trust and how fast the failure cascades — plus what to do about it.
Domain Expiry Monitoring: Why Calendar Reminders Fail
A practical guide to domain expiry monitoring: why calendar reminders and registrar emails fail, and what automated WHOIS monitoring actually catches.
Subdomain takeover explained: dangling DNS and how to fix it
Subdomain takeover happens when DNS points at a cloud resource you no longer control. Learn the dangling-CNAME mechanism, the impact, and how to find and fix it.
SPF record explained: syntax, qualifiers and the 10-lookup trap
SPF record explained for practitioners: v=spf1 syntax, include vs ip4, ~all vs -all, the 10-DNS-lookup limit, and the mistakes that cause permerror.
SSL Certificate Expiry Monitoring: Why Certs Still Lapse in the Age of Automation
Why SSL certificate expiry monitoring still matters in the age of automation: real outages, probing vs CT logs, and the alert lead times that work.
What Happens When a Domain Expires? The Full Timeline
What happens when a domain expires? The full lifecycle from expiry day through grace, redemption and pending delete — costs of recovery and how to prevent it.