Mail domain report: khn.nl

SPF

pass

SPF record published

Found

Record: v=spf1 ip4:23.202.229.18/31 ip4:52.29.184.146 include:spf.protection.outlook.com include:amazonses.com include:_spf_ip.visma.com include:_spf.eu.mailgun.org ip4:13.93.4.51 include:sendgrid.net include:spf.emailsignatures365.com include:_spf.paytsoftware.com a:out.smtp.felton.nl -all
DNS lookups: 9 of 10
Void lookups: 0 of 2

Checks

✓ No deprecated ptr mechanism #1

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

SPF record needs 9 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.khn.nl)

Found

Record: v=DMARC1; p=quarantine; rua=mailto:watchdog4@watchdog.kevlarr.io;
Found at: _dmarc.khn.nl
External report address: mailto:watchdog4@watchdog.kevlarr.io (authorized)

Tag	Value	Meaning
v	DMARC1	Version
p	quarantine	Policy
rua	mailto:watchdog4@watchdog.kevlarr.io	Aggregate report addresses

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.
✓ Aggregate reports enabled #19

Aggregate reports are sent to: mailto:watchdog4@watchdog.kevlarr.io
✓ Subdomain policy: quarantine #20

Subdomains are covered by policy 'quarantine'.
✓ External report addresses authorized #29

Report addresses in other domains have published their authorization.

DKIM

fail

Selectors: dkim, selector1

Found

Selectors: dkim, selector1
_domainkey: NOERROR

Selector	Key	Flags
dkim	RSA 384 bits
selector1	RSA 1024 bits

Checks

✓ Keys found: dkim, selector1 #7

DKIM keys found for this domain with selectors: dkim, selector1
✗

Weak DKIM key

RSA keys shorter than 1024 bits can be cracked and are ignored by receivers (RFC 8301): dkim (384 bits). Rotate to a 2048-bit key.

#23
✓ No problematic flags #24

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

DNSSEC

pass

Signed, DS published at parent

Found

DNSKEY records: Yes (2)
DS at parent: Yes
Algorithms: ECDSAP256SHA256 (13)
Key tags: 34505, 2371
Signatures valid until: 10 December 2026, 12:59 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 2026-12-10 #21

DNSKEY signatures are valid until 2026-12-10T12:59:43Z.

MX

warn

1 mail server

Found

Priority	Host	Records	Reverse DNS
0	khn-nl.mail.protection.outlook.com	A 52.101.73.145 A 52.101.68.10 A 52.101.68.8 A 52.101.209.153 AAAA 2a01:111:f403:ca04::d AAAA 2a01:111:f403:ca48::c AAAA 2a01:111:f403:ca04::b AAAA 2a01:111:f403:ca04::f	mail-am6pr02cu00301.inbound.protection.outlook.com ✓ mail-dbbpr03cu00102.inbound.protection.outlook.com ✓ mail-du0pr03cu00100.inbound.protection.outlook.com ✓ mail-cpjpr04cu00101.inbound.protection.outlook.com ✓ mail-db6pr03cu00105.inbound.protection.outlook.com ✓ mail-miypr03cu00104.inbound.protection.outlook.com ✓ mail-dbbpr03cu00103.inbound.protection.outlook.com ✓ mail-db7pr03cu00507.inbound.protection.outlook.com ✓

Checks

✓ 1 MX record #9

Found 1 MX records for this domain.
✓ All hosts resolve #10

All MX records resolve to valid IP addresses.
✓ All hosts have IPv6 #11

All MX records resolve to IPv6 addresses.
!

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 8 MX addresss 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
khn-nl.mail.protection.outlook.com	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

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