Q: How do I monitor DNS so an expiring domain or bad record doesn't silently kill us?

Q: How do I monitor DNS so an expiring domain or bad record doesn't silently kill us?

A: DNS failures don't always show as 'down' on a normal HTTP check, so monitor it directly.

— Add a domain-expiration monitor with 60/30/7-day alerts. An expired domain is total, embarrassing downtime.
— Monitor that your critical records (A, CNAME, MX) resolve to the values you expect, and alert on change.
— Check resolution from multiple regions; DNS propagation and geo-routing differ.
— Watch nameserver reachability separately. If your DNS host goes down, every site they serve does too.
— Monitor DNSSEC validity if you use it; a bad signature breaks resolution silently.

Follow-up: keep the registrar contact and auto-renew billing on a card that won't expire. The most common 'mystery outage' is a domain that quietly lapsed because the renewal card was declined.

Got a question? Drop it in the comments.