Monitor types

Email security monitors (SPF, DKIM, DMARC)

How FastPing grades your SPF, DKIM, DMARC, MTA-STS and TLS-RPT records, warns below your minimum score and alerts you when the records change.

Last updated: 2 min read

API type
email
You enter
Hostname or IP
Runs at most every
6 hours
Needs
None

How it works

FastPing reads these DNS records for your domain:

  • MX records, and the TXT records at the domain itself (SPF);
  • _dmarc.example.com (DMARC), _mta-sts.example.com (MTA-STS), _smtp._tls.example.com (TLS-RPT) and default._bimi.example.com (BIMI);
  • DKIM keys at <selector>._domainkey.example.com for common selectors (default, google, selector1, selector2, k1, k2, mail, dkim, s1, s2, smtp, mandrill, mxvault, zoho, protonmail, fm1, sig1) plus the selector you enter.

It starts from 100 points, deducts points for each problem and turns the score into a grade. The monitor is up while the score is at or above your minimum score (60 unless you change it) and in warning below it. It sends a change alert when your SPF record, your DMARC record or the set of DKIM selectors found changes. The check runs at most every 6 hours.

How the score is calculated

FindingPoints
No SPF record−25
More than one SPF record (SPF is then invalid)−20
SPF ends with +all (authorises every server)−20
SPF uses ?all (neutral)−8
SPF has no ~all or -all−6
SPF has more than 10 lookup-causing terms−10
No DMARC record−25
DMARC record without a valid p= policy−15
DMARC policy p=none (monitoring only)−10
DMARC without rua= (no aggregate reports)−4
DMARC pct= below 100−4
No DKIM key found on the checked selectors (domains with MX records only)−10
No MTA-STS policy (domains with MX records only)−3
No TLS-RPT record (domains with MX records only)−2

Grades: A from 90, B from 75, C from 60, D from 40, F below 40. A BIMI record is reported but does not change the score. The SPF lookup count is estimated from the terms in your record (include:, a, mx, ptr, exists:, redirect=); includes inside included records are not expanded.

Settings

FieldAPI optionDefaultNotes
Hostname, domain or IPhostRequiredPublic hostname or IP address
DKIM selector (optional)dkimSelectorNoneUp to 63 characters
Warn below scoreminScore600 to 100
Check intervalintervalYour plan's minimumNever more often than every 6 hours

To find your DKIM selector, open the headers of an email sent from your domain and look for the DKIM-Signature header: the selector is the value of s=.

Example records

A domain that sends mail through one provider

DNS records
example.com.         TXT  "v=spf1 include:_spf.mail-provider.example -all"
_dmarc.example.com.  TXT  "v=DMARC1; p=quarantine; rua=mailto:dmarc@example.com"

Start DMARC with p=none while you read the aggregate reports, then move to quarantine and reject once every legitimate source passes.

A domain that never sends mail

DNS records
example.org.         TXT  "v=spf1 -all"
_dmarc.example.org.  TXT  "v=DMARC1; p=reject"

This tells receivers to reject anything that claims to come from the domain. Without MX records, the DKIM, MTA-STS and TLS-RPT findings do not apply.

Check a domain now

The free SPF & DMARC checker runs the same analysis and lists every finding with the records it found.

Still need help?

Write to us and a person will answer, usually within one business day.