Domains, certificates, DNS and email security
What Domain monitor checks, how alerts work and when to use DNS propagation.
- Lesson
- 2/5
- Reading time
- 7 min
- Sections
- 3
- Through the course
- 40%
What's checked
- Registration: expiry, registrar, status codes, nameservers, transfer lock and DNSSEC from official registry data.
- Certificate: expiry, issuer, chain, browser trust and name coverage.
- DNS: A, AAAA, CNAME, MX, NS, TXT and CAA records.
- Email security: SPF (including the 10-lookup limit), DMARC, DKIM and MTA-STS, graded A to F.
- Blocklists: the domain's server addresses against major spam blocklists.
Alerts
Choose the days before expiry to be warned, separately for registration (60, 30, 14, 7 and 1 by default) and certificate (30, 14, 7 and 1). Registrar, nameserver, lock, DNS, issuer, email grade and blocklist changes alert too, and every change is kept on the timeline.
DNS propagation
Ask resolvers in more than 50 locations for a record and see which have picked up a change, how consistent they are and how long old values may be cached. Use it after migrating a site or changing mail records.
Change the A or CNAME record, then run a propagation check. Resolvers that still show the old value may be caching it; the check shows how long old values may last.
Lesson 2 of 5
Domains, certificates, DNS and email security