DNS monitors
Check that a DNS record resolves, and optionally that it resolves to the value you expect.
A DNS monitor resolves a record and reports whether the lookup succeeded — and, if you tell it what to expect, whether the answer was right.
Configuration
| Setting | Allowed values | Default |
|---|---|---|
host |
the name to resolve | required |
recordType |
ANY, A, AAAA, CNAME, MX, TXT, NS, SRV |
ANY |
nameServer |
a specific resolver to ask | system resolver |
expectedValue |
the answer the record must contain | none |
Checking against a specific nameserver
Leaving nameServer empty checks what the world sees through normal recursive
resolution. Setting it asks one server directly, which is how you catch a
provider whose nodes disagree with each other, or confirm that a change has
landed on your authoritative servers before the TTL expires everywhere else.
What to watch
| Record | Why it matters |
|---|---|
A / AAAA on your apex |
Your site is unreachable if this breaks, whatever the servers are doing |
MX |
A dropped MX record silently stops inbound mail |
NS |
Catches an expired or misdelegated zone |
TXT |
SPF, DKIM and domain-verification records that quietly expire |
DNS versus DNS Diff
A DNS monitor checks the answer against a value you specified. Use it when you know what the record should be.
DNS Diff checks the answer against what it was last time and flags any change. Use it when you do not have a fixed expected value but want to know the moment one appears.