Mail domain report: dnb.de

SPF

pass

SPF record published

Found

Record: v=spf1 ip4:193.175.100.144 ip4:193.175.100.0/32 include:_spf.pretix.eu include:oclcspf3.oclc.org include:spf.init.de ~all
DNS lookups: 5 of 10
Void lookups: 0 of 2

Checks

✓ No deprecated ptr mechanism #1

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

SPF record needs 5 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

fail

p=none (_dmarc.dnb.de)

Found

Record: v=DMARC1; p=none;
Found at: _dmarc.dnb.de

Tag	Value	Meaning
v	DMARC1	Version
p	none	Policy

Checks

✗

Policy: none (monitoring only)

DMARC policy is set to 'none', which only monitors but doesn't protect against spoofing. Consider upgrading to 'quarantine' or ideally 'reject'.

#4
✓ Record published #5

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

DMARC record syntax is valid.
!

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

DKIM

warn

No keys found under the checked selectors

Found

Selectors: None found
_domainkey: NOERROR

Checks

!

No key under common selectors

The _domainkey name exists but no DKIM key was found under the common selectors. Selectors are provider-specific; check yours with -selector.

#7

DNSSEC

pass

Signed, DS published at parent

Found

DNSKEY records: Yes (2)
DS at parent: Yes
Algorithms: RSASHA256 (8)
Key tags: 20819, 32778
Signatures valid until: 17 November 2026, 02:49 UTC

Checks

✓ Signed, DS published at parent #8

DNSSEC is enabled for this domain (DNSKEY and DS present), providing additional security for DNS lookups.
✓ Signatures valid until 2026-11-17 #21

DNSKEY signatures are valid until 2026-11-17T02:49:27Z.

MX

warn

1 mail server

Found

Priority	Host	Records	Reverse DNS
10	mail.dnb.de	A 193.175.100.144	mail.dnb.de ✓

Checks

✓ 1 MX record #9

Found 1 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: mail.dnb.de

#11
!

Single MX host, no backup

Only one MX record found. For better email reliability, consider adding at least one backup MX server.

#12
✓ At most 5 MX records #13

Found 1 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 1 MX address have a PTR record that resolves back to them.

TLS

warn

no MTA-STS · no TLS-RPT · DANE on 0 of 1 MX hosts

Found

DANE (TLSA records)

MX host	TLSA	DNSSEC
mail.dnb.de	none	-

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
i

Not configured

TLS-RPT lets senders report TLS delivery problems to you. It is most useful together with MTA-STS or DANE.

#35
i

Not used

No MX host publishes TLSA records. DANE lets senders verify your mail server's certificate through DNSSEC; it requires DNSSEC on the MX host's zone.

#36

BIMI

fail

https://files.dnb.de/dnb.logo.svg

Found

Record: v=bimi1; l=https://files.dnb.de/dnb.logo.svg
Found at: default._bimi.dnb.de
Logo: https://files.dnb.de/dnb.logo.svg

Checks

✗

Invalid BIMI record

Mail clients ignore the BIMI record because of: the record must start with v=BIMI1.

#38
✗

DMARC not strict enough for BIMI

Mail clients will not show the logo. BIMI requires DMARC p=quarantine or p=reject (now p=none), a subdomain policy other than sp=none.

#39