Mail domain report: gfz.de

SPF

pass

SPF record published

Found

Record: v=spf1 a:mail.gfz.de a:otc-de-spf.mms.t-systems-service.com a:gfz-potsdam.managed-otrs.com ~all
DNS lookups: 3 of 10
Void lookups: 0 of 2

Checks

✓ No deprecated ptr mechanism #1

No ptr mechanism found in SPF record.
✓ 3 of 10 DNS lookups #2

SPF record needs 3 DNS lookups (limit is 10).
✓ Ends with ~all #3

SPF record properly uses ~all to restrict unauthorized senders.
✓ Record published #6

SPF record exists for this domain.
✓ Single record #16

Exactly one SPF record is published.
✓ Valid syntax #25

All SPF mechanisms and modifiers are valid.
✓ No void lookups #26

All include/redirect targets exist.
✓ No overly broad IP ranges #27

All ip4/ip6 ranges are narrow enough.

DMARC

warn

p=quarantine (_dmarc.gfz.de)

Found

Record: v=DMARC1; p=quarantine;
Found at: _dmarc.gfz.de

Tag	Value	Meaning
v	DMARC1	Version
p	quarantine	Policy

Checks

!

Policy: quarantine

DMARC policy is set to 'quarantine'. Consider upgrading to 'reject' for stronger protection once you've verified legitimate emails are passing authentication.

#4
✓ Record published #5

DMARC record exists for this domain.
✓ Valid syntax #17

DMARC record syntax is valid.
✓ Applies to 100% of mail #18

DMARC policy applies to all failing mail.
!

No aggregate reports (rua)

DMARC record has no rua tag, so you receive no aggregate reports about who sends mail as your domain. Add rua=mailto:...

#19
✓ Subdomain policy: quarantine #20

Subdomains are covered by policy 'quarantine'.

DKIM

pass

Selectors: mail

Found

Selectors: mail
_domainkey: NOERROR

Selector	Key	Flags
mail	RSA 2048 bits

Checks

✓ Keys found: mail #7

DKIM keys found for this domain with selectors: mail
✓ Strong keys #23

DKIM keys are strong enough: mail: RSA 2048 bits.
✓ No problematic flags #24

No keys in test mode, revoked, or limited to SHA-1.

DNSSEC

warn

Not signed

Found

DNSKEY records: No (0)
DS at parent: No

Checks

!

Not enabled

DNSSEC is not enabled for this domain. Consider enabling DNSSEC to protect against DNS spoofing attacks.

#8

MX

warn

3 mail servers

Found

Priority	Host	Records	Reverse DNS
10	a1791.mx.srv.dfn.de	A 194.95.232.122	a1791.mx.srv.dfn.de ✓
10	b1791.mx.srv.dfn.de	A 194.95.234.122	b1791.mx.srv.dfn.de ✓
10	c1791.mx.srv.dfn.de	A 194.95.238.122	c1791.mx.srv.dfn.de ✓

Checks

✓ 3 MX records #9

Found 3 MX records for this domain.
✓ All hosts resolve #10

All MX records resolve to valid IP addresses.
!

Hosts without IPv6

The following MX hosts could not be resolved to IPv6 addresses: a1791.mx.srv.dfn.de, b1791.mx.srv.dfn.de, c1791.mx.srv.dfn.de

#11
✓ Redundant MX hosts #12

Found 3 MX records, which provides redundancy for email delivery.
✓ At most 5 MX records #13

Found 3 MX records, which is within the recommended range (1-5).
✓ No localhost targets #14

No MX records pointing to localhost found.
✓ No private IP addresses #15

No MX records resolving to private IP addresses found.
✓ No CNAME targets #22

No MX records point to a CNAME.
✓ Reverse DNS confirmed #30

All 3 MX addresss have a PTR record that resolves back to them.

TLS

warn

no MTA-STS · no TLS-RPT · DANE on 3 of 3 MX hosts

Found

DANE (TLSA records)

MX host	TLSA	DNSSEC
a1791.mx.srv.dfn.de	3 0 1 9bec67f55f2afdb7…	Yes
b1791.mx.srv.dfn.de	3 0 1 9bec67f55f2afdb7…	Yes
c1791.mx.srv.dfn.de	3 0 1 9bec67f55f2afdb7…	Yes

Checks

!

Not configured

MTA-STS is not configured, so other mail servers fall back to unencrypted delivery when TLS fails or is stripped by an attacker. Publish a _mta-sts TXT record and a policy at https://mta-sts.<domain>/.well-known/mta-sts.txt.

#32
!

Not configured

MTA-STS or DANE is used without TLS-RPT, so you get no reports when senders fail to deliver because of TLS problems. Publish _smtp._tls TXT "v=TLSRPTv1; rua=mailto:...".

#35
✓ DANE on all MX hosts #36

All 3 MX hosts publish DNSSEC-validated TLSA records.

BIMI

info

No BIMI record

Checks

i

Not configured

BIMI shows your logo next to your mail in supporting mail clients. It requires DMARC enforcement.

#38