dyndns.org

dyndns.org · Last checked 2026-10-04 02:13 UTC

dyndns.org

Poor, with 2 things to fix

dyndns.org scored 47/100 (grade D). The main issues are SPF needs more than 10 DNS lookups and no DKIM key found for the common selectors, plus 3 more. Detected senders: Microsoft 365.

Checked 2026-10-04 02:13 UTC · fresh check

1 passed1 needs attention1 failing5 for informationDetected senders: Microsoft 365
Fix this firstThe change with the biggest effect

Reduce SPF DNS lookups

Evaluating SPF for dyndns.org takes 11 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: outbound.mailhop.org, sendlabs.com, dynect.net. Changes: Removed ptr:opensrs.net: RFC 7208 says ptr should not be used; it is slow and some receivers ignore it. Replaced ~all with -all so mail from servers not listed is rejected.

TypeTXT
Name / Host
dyndns.org

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

Value
v=spf1 mx/24 a:lists.dyndns.com ip4:63.208.196.0/24 include:outbound.mailhop.org include:sendlabs.com include:dynect.net include:spf.protection.outlook.com -all
Replaces
v=spf1 mx/24 a:lists.dyndns.com ip4:63.208.196.0/24 ptr:opensrs.net include:outbound.mailhop.org include:sendlabs.com include:dynect.net include:spf.protection.outlook.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 dyndns.org goes to dyndns-org.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 needs more than 10 DNS lookupsFailing
  • Fail: SPF needs more than 10 DNS lookups

    Evaluating the SPF record for dyndns.org needs more than 10 DNS lookups (counting nested includes). Receivers stop at 10 with a permanent error, so SPF fails. Remove unused includes or replace them with IP ranges.

    How to fix this
  • Warning: SPF uses the ptr mechanism

    The SPF record of dyndns.org uses ptr. RFC 7208 §5.5 says ptr "SHOULD NOT be used": it is slow, unreliable, and some receivers ignore it. Replace it with ip4/ip6 ranges or an include from your provider.

  • Warning: Could not look up an included SPF record

    The TXT query for sendlabs.com, which your record includes or redirects to, returned SERVFAIL. Receivers that see the same failure return a temporary error and may defer or reject mail.

  • Warning: SPF has no "all" term

    Without a closing "all" term, mail from unlisted servers gets a neutral result. End the record with "-all" or "~all".

DKIMAre your emails signed?No DKIM key found for the common selectorsNeeds attention
  • Warning: No DKIM key found for the common selectors

    None of the 47 selectors probed under dyndns.org publish a DKIM key. DNS cannot list selectors, so a key under a custom selector may exist: find the s= value in the DKIM-Signature header of a message you sent and check that selector. If DKIM is not set up, enable it at each service that sends mail for dyndns.org.

DMARCWhat happens to fakes?No issues foundPass

Nothing to report.

AlignmentDoes it match your From?SPF alignment is unknownInfo
  • Info: SPF alignment is unknown

    The SPF record of dyndns.org can pass for some senders (those matched before the failing part), but another evaluation path ends in a permanent error (spf.lookups.over-limit). Senders that reach that path fail SPF, so whether your mail aligns through SPF is unknown. Fix the error so every path evaluates.

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

    No BIMI record at default._bimi.dyndns.org. 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.dyndns.org. 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?No TLS-RPT recordInfo
  • Info: No TLS-RPT record

    No TLS reporting record at _smtp._tls.dyndns.org. TLS-RPT (RFC 8460) tells senders where to send daily reports about failed encrypted deliveries to you.

    How to fix this

Other fixes

Enable DKIM for Microsoft 365instruction

Microsoft 365 generates the DKIM key for each account, so the exact record must come from Microsoft 365. Without DKIM, mail it sends for dyndns.org cannot pass DMARC through DKIM.

Applies to: selector1._domainkey.dyndns.org

  1. In Microsoft 365, enable DKIM signing for dyndns.org: tenant-specific: copy Selector1CNAME/Selector2CNAME from Microsoft 365 Defender > Email authentication > DKIM. Publish exactly the record Microsoft 365 shows (TXT or CNAME) at the host name it gives, then turn signing on. Instructions: https://learn.microsoft.com/microsoft-365/security/office-365-security/email-authentication-dkim-configure

Enable DKIM for Microsoft 365instruction

Microsoft 365 generates the DKIM key for each account, so the exact record must come from Microsoft 365. Without DKIM, mail it sends for dyndns.org cannot pass DMARC through DKIM.

Applies to: selector2._domainkey.dyndns.org

  1. In Microsoft 365, enable DKIM signing for dyndns.org: tenant-specific: copy Selector1CNAME/Selector2CNAME from Microsoft 365 Defender > Email authentication > DKIM. Publish exactly the record Microsoft 365 shows (TXT or CNAME) at the host name it gives, then turn signing on. Instructions: https://learn.microsoft.com/microsoft-365/security/office-365-security/email-authentication-dkim-configure

Publish the MTA-STS recordTXT

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

TypeTXT
Name / Host
_mta-sts.dyndns.org

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

Value
v=STSv1; id=202610040213

Host the MTA-STS policy filepolicy-file

Serve this file over HTTPS with a valid certificate for mta-sts.dyndns.org. 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.dyndns.org/.well-known/mta-sts.txt
Contents
version: STSv1
mode: testing
mx: dyndns-org.mail.protection.outlook.com
max_age: 604800

Set up a TLS report addressinstruction

Sending servers will report TLS failures when delivering to dyndns.org, which you need before enforcing MTA-STS. The address must accept TLS reports; a DMARC report address does not necessarily do so.

Applies to: _smtp._tls.dyndns.org

  1. Pick an address that will receive TLS reports: a mailbox you read (for example tls-reports@dyndns.org, created first) or a TLS reporting service. 2. Publish a TXT record at _smtp._tls.dyndns.org with the value v=TLSRPTv1; rua=mailto:<that address>.

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.dyndns.org

  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://dyndns.org/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.dyndns.org with v=BIMI1, l= set to the logo URL and a= set to the certificate URL.