spinther.app
Good, with 2 things to fix
spinther.app scored 84/100 (grade B). The main issues are no DMARC aggregate report address and MX host is a CNAME.
Checked 2026-10-03 13:49 UTC
Set up a DMARC report address
Without a rua address nobody receives aggregate reports, so you cannot see who sends as spinther.app or tell when it is safe to tighten the policy. Adding reporting does not change how receivers treat your mail.
Applies to: _dmarc.spinther.app
- Get an address that collects DMARC aggregate reports: add spinther.app to MailVakt to receive one, or sign up with any DMARC report service. 2. Edit the TXT record at _dmarc.spinther.app and add rua=mailto:<that address>, keeping every other tag (p=reject, sp=reject) as it is. 3. A report service on another domain must authorize spinther.app; most publish that record for you.
All checks
MXCan servers find your inbox?MX host is a CNAMENeeds attention
- Warning: MX host is a CNAME
RFC 2181 forbids an MX target that is an alias. Some senders refuse or delay delivery to mx01.mail.icloud.com, mx02.mail.icloud.com. Point the MX at the canonical hostname instead.
SPFWho may send as you?SPF ends in softfail (~all)Info
- Info: SPF ends in softfail (~all)
"~all" is common and works well with DMARC. "-all" is stricter; switch when you are sure every sender is listed.
DKIMAre your emails signed?DKIM key publishedPass
- Pass: DKIM key published
spinther.app publishes a DKIM key under sig1.
DMARCWhat happens to fakes?No DMARC aggregate report addressNeeds attention
- Warning: No DMARC aggregate report address
Without a rua address you receive no aggregate reports, so you cannot see who sends as your domain or safely tighten the policy.
How to fix this - Info: DMARC uses strict alignment
With adkim=s or aspf=s the DKIM d= domain or the bounce domain must equal the From domain exactly; a subdomain is not enough. Third-party senders that sign or bounce from a subdomain (or their own domain) will then fail DMARC unless they are configured to use your exact domain.
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.spinther.app. 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.spinther.app. 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.spinther.app. TLS-RPT (RFC 8460) tells senders where to send daily reports about failed encrypted deliveries to you.
How to fix this
Other fixes
Publish the MTA-STS recordTXT
Tells sending servers that spinther.app publishes an MTA-STS policy at https://mta-sts.spinther.app/.well-known/mta-sts.txt. Change the id whenever the policy file changes.
_mta-sts.spinther.app
Some DNS providers want just “_mta-sts” here.
v=STSv1; id=202610031349
Host the MTA-STS policy filepolicy-file
Serve this file over HTTPS with a valid certificate for mta-sts.spinther.app. It lists your MX hosts and starts in testing mode; switch to mode: enforce once TLS-RPT reports show no failures.
https://mta-sts.spinther.app/.well-known/mta-sts.txt
version: STSv1 mode: testing mx: mx01.mail.icloud.com mx: mx02.mail.icloud.com max_age: 604800
Set up a TLS report addressinstruction
Sending servers will report TLS failures when delivering to spinther.app, 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.spinther.app
- Pick an address that will receive TLS reports: a mailbox you read (for example tls-reports@spinther.app, created first) or a TLS reporting service. 2. Publish a TXT record at _smtp._tls.spinther.app 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.spinther.app
- 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://spinther.app/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.spinther.app with v=BIMI1, l= set to the logo URL and a= set to the certificate URL.