mozilla.org
Receivers are told to reject mail that fails authentication for this domain.
Receivers are told to reject mail that fails authentication for this domain. Keep watching aggregate reports so a new sending service does not silently start failing.
Score held up: DMARC is enforcing at p=reject, so nobody else can send as this domain. That is the hard part, and it is done. What is left below is about your own mail arriving, not about anyone spoofing you.
157 DNS queries · 3209 ms
- 1Selector 'google' uses a 1024-bit RSA keyRotate to 2048-bit at your next key rotation.
- 2No explicit subdomain policy (sp=)Consider adding 'sp=reject' if no subdomain sends mail.
- 3No MTA-STS policyPublish a TXT record at _mta-sts.mozilla.org and a policy file at https://mta-sts.mozilla.org/.well-known/mta-sts.txt.
- 4SPF ends in '~all' (softfail)Once your aggregate reports show no unexplained legitimate sources, tighten to '-all'.
Identity ·Sending services detected
Read from your SPF includes and MX hosts, then checked for a published DKIM key.
Identity ·DMARC
- Policy
- reject
- Coverage
- 100%
- Alignment
- dkim=r spf=r
Identity ·DKIM
111 selectors probed
googleGoogle WorkspaceRSA 1024Identity ·SPF
Worst-case evaluation across every include.
- include:_spf.mozilla.com
- include:_netblocks.mozilla.com
- include:_netblocks3.mozilla.com
- include:_spf.google.com
- include:spf.fundraiseup.com
Findings (6)
MediumSelector 'google' uses a 1024-bit RSA key›
1024-bit is the RFC 8301 floor, not a good target. 2048-bit is the current recommendation and is universally supported.
Rotate to 2048-bit at your next key rotation.
RFC 8301
LowNo explicit subdomain policy (sp=)›
Subdomains inherit p=, which is usually what you want. Setting 'sp=reject' explicitly protects unused subdomains even while the parent is still at p=none.
Consider adding 'sp=reject' if no subdomain sends mail.
LowSPF ends in '~all' (softfail)›
Softfail is the correct setting while you are still discovering senders, but it asks receivers to accept unauthorised mail and merely note it.
Once your aggregate reports show no unexplained legitimate sources, tighten to '-all'.
LowNo MTA-STS policy›
Without MTA-STS, mail to your domain can be downgraded to plaintext by an active network attacker, because SMTP's STARTTLS is opportunistic by default.
Publish a TXT record at _mta-sts.mozilla.org and a policy file at https://mta-sts.mozilla.org/.well-known/mta-sts.txt.
RFC 8461
LowNo TLS-RPT record›
Sending servers have no address to report TLS failures on mail to your domain, so transport problems stay invisible to you until someone complains.
Publish 'v=TLSRPTv1; rua=mailto:<address>' at _smtp._tls.mozilla.org.
RFC 8460
InfoZone is not signed with DNSSEC›
This is the common case and not a misconfiguration -- most working mail domains are unsigned. It is worth knowing because your authentication records are only as trustworthy as the DNS answers carrying them, and because DNSSEC is the prerequisite for DANE.
If your DNS provider supports one-click DNSSEC, enabling it is low risk. If it does not, this is not worth changing providers over.
RFC 4033
Show 9 passing checks
PassAggregate reporting is configured›
Aggregate reports are requested at: [email protected], [email protected].
PassExternal report destination vali.email is correctly authorised›
Authorised by mozilla.org._report._dmarc.vali.email
PassExternal report destination mozilla.com is correctly authorised›
Authorised by mozilla.org._report._dmarc.mozilla.com
PassDMARC policy is p=reject›
Mail failing authentication is rejected outright. This is the correct end state.
PassSPF lookup count is healthy (7/10)›
Worst-case evaluation stays within the limit with headroom to spare.
PassGoogle Workspace's DKIM key is published at google._domainkey›
Detected via SPF include:_spf.google.com, MX alt1.aspmx.l.google.com, MX alt2.aspmx.l.google.com, MX aspmx.l.google.com, MX aspmx3.googlemail.com. A valid public key for this service is published at google._domainkey.mozilla.org.
Pass1 DKIM key(s) published›
Found at: google.
PassBIMI is published with a certificate reference›
The record at default._bimi.mozilla.org names a logo and a Verified Mark Certificate (a=), and DMARC is enforcing, which BIMI requires. We read the record only; the logo and certificate themselves were not fetched or checked.
PassCertificate issuance is restricted by CAA›
Only amazon.com, amazonaws.com, amazontrust.com, awstrust.com, certainly.com, comodoca.com, digicert.com, letsencrypt.org, pki.goog, sectigo.com may issue certificates for this domain, so a certificate for your mail hosts or your MTA-STS policy endpoint from any other authority would be a mis-issuance.
RFC 8659
Transport and zone
Where your mail lands, and whether the DNS carrying your records can be trusted.
This is the configuration. It is not the whole picture.
A DNS scan cannot tell you whether mozilla.org’s mail actually aligns, because alignment is decided per message at the receiver. Collect DMARC aggregate reports to see every source sending as this domain.