Mail domain report: cpb.nl

SPF

pass

SPF record published

Found

Record: v=spf1 a:cpb-mail-l02p.cpb.nl ip4:192.104.140.227 ip4:192.104.140.228 ip4:192.104.140.243 ip4:145.69.51.60 ip4:145.69.39.60 ip4:131.224.7.5 ip4:192.104.140.239 ip4:192.140.140.240 a:mediars.org include:spf.protection.outlook.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

pass

p=reject (_dmarc.cpb.nl)

Found

Record: v=DMARC1; p=reject; pct=100; rua=mailto:dmarcreport@cpb.nl; ruf=mailto:beheer@cpb.nl;
Found at: _dmarc.cpb.nl

Tag	Value	Meaning
v	DMARC1	Version
p	reject	Policy
pct	100	Percentage of mail the policy applies to
rua	mailto:dmarcreport@cpb.nl	Aggregate report addresses
ruf	mailto:beheer@cpb.nl	Failure report addresses

Checks

✓ Policy: reject #4

DMARC policy is set to 'reject', which provides the strongest protection against email spoofing.
✓ 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:dmarcreport@cpb.nl
✓ Subdomain policy: reject #20

Subdomains are covered by policy 'reject'.
✓ Report addresses in own domain #29

All report addresses are in your own organizational domain.

DKIM

warn

Selectors: default

Found

Selectors: default
_domainkey: NOERROR

Selector	Key	Flags
default	RSA 1024 bits

Checks

✓ Keys found: default #7

DKIM keys found for this domain with selectors: default
!

1024-bit DKIM key

1024-bit RSA keys are the minimum and are considered weak today: default (1024 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 (1)
DS at parent: Yes
Algorithms: ECDSAP256SHA256 (13)
Key tags: 47023
Signatures valid until: 29 October 2026, 00:00 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 2026-10-29 #21

DNSKEY signatures are valid until 2026-10-29T00:00:00Z.

MX

warn

1 mail server

Found

Priority	Host	Records	Reverse DNS
10	smtp.cpb.nl	A 192.104.140.228 AAAA 2001:610:1d8:ffff::48:15	smtp.cpb.nl ✓ smtp.cpb.nl ✓

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

TLS

warn

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

Found

DANE (TLSA records)

MX host	TLSA	DNSSEC
smtp.cpb.nl	3 1 1 0c08b87490653b84…	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 1 MX host 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