https://help.happydomain.org/en/reference/checkers/index.html 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/. Hugo en Thu, 11 Jun 2026 17:27:00 +0900 https://help.happydomain.org/en/reference/checkers/domain-expiry/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/domain-expiry/index.html Warns when a domain name is approaching its registration expiry date. https://help.happydomain.org/en/reference/checkers/domain-lock/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/domain-lock/index.html Verifies that a domain carries the expected EPP lock statuses that protect it against unauthorized transfers or changes. https://help.happydomain.org/en/reference/checkers/domain-contact/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/domain-contact/index.html Verifies that the registered domain contacts (registrant, admin, tech) match the values you expect, with detection of privacy-protected records. https://help.happydomain.org/en/reference/checkers/domain-availability/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/domain-availability/index.html Notifies you when a watched domain name becomes available for registration. https://help.happydomain.org/en/reference/checkers/external-expiry/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/external-expiry/index.html Retrieves the WHOIS/RDAP registration facts for the external domains your zone points to, so their expiry can be evaluated. https://help.happydomain.org/en/reference/checkers/dnssec/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/dnssec/index.html Audits the operational hygiene of a signed zone: algorithms, key sizes, signature freshness, NSEC/NSEC3 parameters and per-name-server consistency. https://help.happydomain.org/en/reference/checkers/delegation/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/delegation/index.html Audits a zone's delegation: NS consistency between parent and child, glue correctness, DS/DNSKEY hand-off, reachability and authoritativeness of each delegated server. https://help.happydomain.org/en/reference/checkers/authoritative-consistency/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/authoritative-consistency/index.html Probes every authoritative name server of a zone and verifies they agree with each other and with the parent on NS, SOA, reachability, EDNS0 and authoritativeness. https://help.happydomain.org/en/reference/checkers/ns-restrictions/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/ns-restrictions/index.html Probes every authoritative name server of a zone to confirm it is properly locked down: zone transfers refused, no open recursion, and RFC 8482 handling of ANY. https://help.happydomain.org/en/reference/checkers/resolver-propagation/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/resolver-propagation/index.html Probes a worldwide catalog of public recursive resolvers across several transports and regions, then compares their answers to the zone's authoritative servers. https://help.happydomain.org/en/reference/checkers/reverse-zone/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/reverse-zone/index.html Inspects the PTR records of an in-addr.arpa or ip6.arpa reverse zone for FCrDNS, target resolvability, hostname syntax, generic names and TTL hygiene. https://help.happydomain.org/en/reference/checkers/ptr/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/ptr/index.html Validates reverse DNS for an IP: PTR presence, target syntax, forward resolution and Forward-Confirmed Reverse DNS (FCrDNS). https://help.happydomain.org/en/reference/checkers/alias/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/alias/index.html Walks a CNAME/DNAME/ALIAS chain and validates hop count, TTLs, target resolvability, apex coexistence and DNSSEC signing. https://help.happydomain.org/en/reference/checkers/dangling/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/dangling/index.html Scans a zone for CNAME/MX/SRV/NS records whose targets resolve to NXDOMAIN or whose external domain has expired and could be re-registered. https://help.happydomain.org/en/reference/checkers/caa/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/caa/index.html Cross-references the TLS certificates observed on a domain against its CAA issue/issuewild policy to detect unauthorized issuance. https://help.happydomain.org/en/reference/checkers/dane/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/dane/index.html Matches a service's TLSA records against the certificate chain actually presented by each endpoint, per RFC 6698. https://help.happydomain.org/en/reference/checkers/tls/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/tls/index.html Dials every TLS endpoint discovered for a domain, completes the handshake (with STARTTLS upgrade where needed) and audits certificate chain, hostname coverage, expiry and protocol strength. https://help.happydomain.org/en/reference/checkers/http/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/http/index.html Probes a web server over HTTP and HTTPS and evaluates reachability, the redirect chain, and the full battery of HTTP security response headers and cookie hygiene rules. https://help.happydomain.org/en/reference/checkers/ping/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/ping/index.html Sends ICMP probes to every address of a service and reports reachability, average round-trip time, packet loss, and IPv6 coverage. https://help.happydomain.org/en/reference/checkers/smtp/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/smtp/index.html Probes every MX target of a domain on port 25 the way an operator would with swaks: TCP connect, banner, EHLO, STARTTLS, mail-transaction and open-relay probes, reverse DNS and IPv6 coverage. https://help.happydomain.org/en/reference/checkers/happydeliver/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/happydeliver/index.html Send a real test message from your domain to a happyDeliver instance and grade how well it would be delivered to a real inbox. https://help.happydomain.org/en/reference/checkers/email-autoconfig/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/email-autoconfig/index.html Verify that a domain publishes discoverable mail-client configuration through Thunderbird autoconfig, Microsoft Autodiscover and RFC 6186 SRV records. https://help.happydomain.org/en/reference/checkers/email-keys/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/email-keys/index.html Validate DNS-published OpenPGP keys (OPENPGPKEY) and S/MIME certificates (SMIMEA) used for end-to-end mail encryption, including their DNSSEC authentication. https://help.happydomain.org/en/reference/checkers/dav/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/dav/index.html Discovers and probes a domain's CalDAV and CardDAV servers: well-known/SRV discovery, HTTPS reachability, advertised DAV capabilities, and (with credentials) the authenticated principal, home-set, collections and REPORT flow. https://help.happydomain.org/en/reference/checkers/ldap/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/ldap/index.html Probes a domain's LDAP directory end-to-end: SRV discovery, transport encryption (StartTLS / LDAPS), RootDSE introspection, anonymous exposure, plaintext-bind refusal, and optional authenticated bind. https://help.happydomain.org/en/reference/checkers/kerberos/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/kerberos/index.html Audits a Kerberos realm from its DNS records: SRV layout, KDC/kadmin/kpasswd reachability, an anonymous AS-REQ probe (realm, enctypes, pre-auth, clock skew), and an optional authenticated round-trip. https://help.happydomain.org/en/reference/checkers/sip/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/sip/index.html Probes a domain's SIP/VoIP deployment end-to-end: RFC 3263 NAPTR/SRV resolution, endpoint reachability over UDP/TCP/TLS, and a SIP OPTIONS ping with capability inspection. https://help.happydomain.org/en/reference/checkers/ssh/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/ssh/index.html Connects to the advertised SSH ports of a server and audits reachability, banner-to-CVE matches, the full algorithm posture, observed host keys, SSHFP alignment and authentication methods. https://help.happydomain.org/en/reference/checkers/xmpp/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/xmpp/index.html Probes a domain's XMPP deployment: SRV discovery, reachability, STARTTLS, SASL mechanisms and federation authentication. https://help.happydomain.org/en/reference/checkers/matrix-federation/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/matrix-federation/index.html Verifies that a Matrix homeserver federates correctly, using the Matrix Federation Tester. https://help.happydomain.org/en/reference/checkers/stun-turn/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/stun-turn/index.html Probes STUN and TURN servers end-to-end: discovery, reachability, TLS/DTLS, STUN binding and authenticated TURN relay. https://help.happydomain.org/en/reference/checkers/blacklist/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/blacklist/index.html Checks whether a domain is currently listed on widely-used reputation systems: DNS-based domain blocklists, downloaded phishing/malware feeds, and threat-intelligence APIs. https://help.happydomain.org/en/reference/checkers/legacy-records/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/legacy-records/index.html Scans a zone for DNS record types deprecated by the IETF and reports each one with its RFC reference and a migration suggestion. https://help.happydomain.org/en/reference/checkers/dnsviz/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/dnsviz/index.html Run DNSViz against a domain and walk the whole DNSSEC chain from the root down to the leaf, surfacing every error and warning at the exact zone where it occurs. https://help.happydomain.org/en/reference/checkers/zonemaster/index.html Thu, 11 Jun 2026 09:00:00 +0200 https://help.happydomain.org/en/reference/checkers/zonemaster/index.html Run the Zonemaster test suite against a domain through its JSON-RPC API and group the results by test category (delegation, consistency, DNSSEC…).