duckduckgo.com

duckduckgo.com · Last checked 2026-10-04 02:10 UTC

duckduckgo.com

Good, with 2 things to fix

duckduckgo.com scored 76/100 (grade B). The main issues are DKIM record cannot be parsed and DKIM key shorter than 2048 bits, plus 1 more. Detected senders: Microsoft 365, Mailgun and Zendesk.

Checked 2026-10-04 02:10 UTC · fresh check

3 passed2 need attention0 failing3 for informationDetected senders: Microsoft 365, Mailgun, Zendesk
Fix this firstThe change with the biggest effect

Reduce SPF DNS lookups

Evaluating SPF for duckduckgo.com takes 8 DNS lookups including nested includes; receivers stop at 10 and fail SPF. No detected sending service accounts for these includes; remove each one you no longer send through: mail.duckduckgo.com, spf.mailer.duckduckgo.com, duck.com. Changes: Added include:mailgun.org for Mailgun.

TypeTXT
Name / Host
duckduckgo.com

Some DNS providers want “@” here instead of the full domain.

Value
v=spf1 include:mail.duckduckgo.com include:spf.mailer.duckduckgo.com include:spf.protection.outlook.com include:duck.com include:mail.zendesk.com include:mailgun.org -all
Replaces
v=spf1 include:mail.duckduckgo.com include:spf.mailer.duckduckgo.com include:spf.protection.outlook.com include:duck.com include:mail.zendesk.com -all

How to apply it

  1. Sign in where your domain’s DNS is managed. This is often where you bought the domain, such as Cloudflare, GoDaddy or Namecheap.
  2. Find the existing TXT record with that name and replace its value.
  3. Save, then come back and re-check. DNS changes can take up to a few hours to show.

All checks

MXCan servers find your inbox?Only one MX hostInfo
  • Info: Only one MX host

    All mail for duckduckgo.com goes to duckduckgo-com.mail.protection.outlook.com. Most hosted providers make that one name highly available; if you run your own server, consider a backup MX.

SPFWho may send as you?SPF is close to the 10-lookup limitNeeds attention
  • Warning: SPF is close to the 10-lookup limit

    Evaluating the SPF record for duckduckgo.com needs 8 of the 10 allowed DNS lookups. Adding one more service, or a provider growing its own record, will break SPF.

    How to fix this
DKIMAre your emails signed?DKIM key shorter than 2048 bitsNeeds attention
  • Warning: DKIM key shorter than 2048 bits

    selector1 (1024-bit) uses an RSA key below 2048 bits. Short keys can be factored and some receivers treat them as weak. Rotate to a 2048-bit key at your sending provider.

  • Warning: DKIM record cannot be parsed

    s1: p= is not valid base64. Receivers ignore a record they cannot parse, so mail signed with it fails DKIM. Copy the record again from your provider.

  • Pass: DKIM key published

    duckduckgo.com publishes a DKIM key under selector1.

DMARCWhat happens to fakes?No issues foundPass

Nothing to report.

AlignmentDoes it match your From?No issues foundPass

Nothing to report.

BIMICan inboxes show your logo?No BIMI recordInfo
  • Info: No BIMI record

    No BIMI record at default._bimi.duckduckgo.com. BIMI is optional: it shows your logo next to your mail in supporting inboxes once DMARC is enforced.

    How to fix this
MTA-STSIs mail to you encrypted?No MTA-STS recordInfo
  • Info: No MTA-STS record

    No MTA-STS record at _mta-sts.duckduckgo.com. MTA-STS (RFC 8461) makes sending servers require TLS and a valid certificate when delivering to you, which blocks downgrade attacks.

    How to fix this
TLS-RPTWill you hear about failures?TLS-RPT is configuredPass
  • Pass: TLS-RPT is configured

    TLS reports will be sent to mailto:n1um42s6@tls.us.dmarcian.com.

Other fixes

Publish the MTA-STS recordTXT

Tells sending servers that duckduckgo.com publishes an MTA-STS policy at https://mta-sts.duckduckgo.com/.well-known/mta-sts.txt. Change the id whenever the policy file changes.

TypeTXT
Name / Host
_mta-sts.duckduckgo.com

Some DNS providers want just “_mta-sts” here.

Value
v=STSv1; id=202610040210

Host the MTA-STS policy filepolicy-file

Serve this file over HTTPS with a valid certificate for mta-sts.duckduckgo.com. It lists your MX hosts and starts in testing mode; switch to mode: enforce once TLS-RPT reports show no failures.

Location
https://mta-sts.duckduckgo.com/.well-known/mta-sts.txt
Contents
version: STSv1
mode: testing
mx: duckduckgo-com.mail.protection.outlook.com
max_age: 604800

Prepare BIMIinstruction

BIMI shows your logo next to messages in supporting inboxes, but only for mail that passes DMARC under an enforced policy.

Applies to: default._bimi.duckduckgo.com

  1. Enforce DMARC first: p=quarantine or p=reject at 100% (no pct below 100). 2. Convert your logo to an SVG Tiny PS file and host it over HTTPS, for example https://duckduckgo.com/bimi/logo.svg. 3. For Gmail and Apple Mail, obtain a VMC or CMC certificate for the logo. 4. Publish a TXT record at default._bimi.duckduckgo.com with v=BIMI1, l= set to the logo URL and a= set to the certificate URL.