Types de moniteurs
DNS record monitors
Get alerted when A, AAAA, CNAME, MX, NS, TXT, SOA, CAA or SRV records change, disappear or stop containing an expected value.
- API type
dns- You enter
- Hostname or IP
- Runs at most every
- Plan minimum
- Needs
- None
FastPing asks public resolvers for one record type of your hostname: Cloudflare (1.1.1.1) first, then Google (8.8.8.8) and Quad9 (9.9.9.9) if the previous one does not answer. The answers are sorted, so a different order alone is never reported as a change.
- The first check stores the current answers as the reference.
- Every later check compares the answers with the previous ones. Any difference sends a change alert listing the new answers, for example
DNS A records changed to 203.0.113.10, 203.0.113.11. - The monitor goes down when there are no records of that type, when the lookup fails, or when your "Must contain" text is missing.
Because public resolvers are used, the monitor sees what the internet sees. Internal or split-horizon DNS zones are not visible to it.
| Field | API option | Default | Notes |
|---|---|---|---|
| Hostname, domain or IP | host | Required | Public hostname or IP address |
| Record type | recordType | A | One of: A, AAAA, CNAME, MX, NS, TXT, SOA, CAA, SRV |
| Must contain (optional) | expected | None | Up to 300 characters |
| Check interval | interval | Your plan's minimum | From your plan's minimum up to 24 hours |
Must contain is matched as text against each answer: the monitor stays up as long as at least one answer contains it. Answers look like this:
| Type | Answer format |
|---|---|
| A / AAAA | 203.0.113.10 |
| CNAME / NS | shops.example-host.net |
| MX | 10 mx1.example.com (priority, then host) |
| TXT | v=spf1 include:_spf.example.net -all (long records joined) |
| SOA | ns1.example.net hostmaster.example.com serial=2026101701 refresh=7200 retry=3600 expire=1209600 min=3600 |
| CAA | 0 issue "letsencrypt.org" |
| SRV | 0 5 25565 mc.example.com (priority, weight, port, target) |
- Nameserver hijack or accidental migration: type NS on your domain. Any change to the delegation sends an alert.
- Every zone edit: type SOA. The serial changes whenever the zone is edited, so you hear about changes nobody announced.
- Mail routing: type MX with Must contain set to your primary mail host.
- SPF or verification records: type TXT with Must contain
v=spf1, or the verification string a service gave you. - Who may issue certificates: type CAA, to notice when the list of allowed certificate authorities changes.
Avoid change alerts on A records of CDNs and load balancers that rotate addresses: every rotation would be reported. Monitor the CNAME or NS records instead, or set Must contain to a value that does not rotate.
| Message | What it means | What to do |
|---|---|---|
No MX records | The resolver answered, but the name has no record of that type. | Check the record at your DNS provider, and that the monitor uses the right name (example.com versus www.example.com). |
DNS error: ESERVFAIL | The resolvers could not get a valid answer: broken or unreachable authoritative servers, or a DNSSEC validation failure. | Check your nameservers and DNSSEC (DS records at the registrar must match your keys). |
DNS error: ETIMEOUT | No resolver answered in time. | Usually temporary. If it persists, your authoritative servers are not answering. |
Expected "mx1.example.com" not in MX answers | Records exist, but none contains your Must contain text. | Update the record, or the monitor if the change was intended. |
Compare what different public resolvers return with the DNS propagation checker, or list all records with the DNS lookup.