Checkers
Checkers are the building blocks of happyDomain’s monitoring system. Each one collects data about a domain, a zone or a service, evaluates it against a set of rules, and reports a clear status (OK, Warning, Critical or Error).
This chapter documents every checker shipped with happyDomain: what it verifies, the scope it applies to, the options you can tune, and the rules it evaluates. For the day-to-day workflow of configuring, scheduling and reading checks in the interface, see /en/pages/checks/.
Scopes
Every checker declares the scope it operates on:
- Domain-level — concerns the domain itself, independent of its DNS records (registration status, expiry, transfer lock…).
- Zone-level — needs the full zone content (DNSSEC validation, delegation consistency…).
- Service-level — targets a specific service published on a subdomain (HTTP, TLS, ping…), and is configured from that service’s own Checks tab.
Statuses
Checkers report one of the following statuses, in order of severity:
| Status | Meaning |
|---|---|
| OK | Everything is within acceptable parameters |
| Info | Informational finding, no action needed |
| Warning | A threshold is approaching; attention recommended |
| Critical | A threshold has been exceeded; action required |
| Error | The check itself failed (collection error, bad configuration) |
| Unknown | The check could not determine a result |
- Domain expiry
- Domain transfer lock
- Domain contacts
- Domain availability
- External-reference expiry
- DNSSEC validation
- Delegation
- Authoritative consistency
- Name-server restrictions
- Resolver propagation
- Reverse zone
- PTR records
- Alias chain
- Dangling records
- CAA
- DANE / TLSA
- TLS posture
- HTTP / HTTPS
- Ping
- SMTP
- Outbound deliverability (happyDeliver)
- Mail autoconfiguration
- Mail keys (DKIM / OpenPGP)
- CalDAV / CardDAV
- LDAP
- Kerberos
- SIP
- SSH
- XMPP
- Matrix federation
- STUN / TURN
- Blacklist (DNSBL)
- Legacy records
- DNSViz
- Zonemaster