Mail domain report: bibliotheek.nl

SPF

info

SPF record published

Found

Record: v=spf1 redirect=_sj0o01maq.sdmarc.net
DNS lookups: 6 of 10
Void lookups: 0 of 2

Checks

✓ No deprecated ptr mechanism #1

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

SPF record needs 6 DNS lookups (limit is 10).
i

Delegated via redirect

SPF record has no 'all' mechanism but redirects to _sj0o01maq.sdmarc.net, whose policy applies.

#3
✓ 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.bibliotheek.nl)

Found

Record: v=DMARC1; p=reject; rua=mailto:a.j0o01maq@sdmarc.net,mailto:dmarc@smtpeter.com; adkim=r; aspf=r
Found at: _dmarc.bibliotheek.nl
External report address: mailto:a.j0o01maq@sdmarc.net (authorized)
External report address: mailto:dmarc@smtpeter.com (authorized)

Tag	Value	Meaning
v	DMARC1	Version
p	reject	Policy
rua	mailto:a.j0o01maq@sdmarc.net,mailto:dmarc@smtpeter.com	Aggregate report addresses
adkim	r	DKIM alignment (r = relaxed, s = strict)
aspf	r	SPF alignment (r = relaxed, s = strict)

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:a.j0o01maq@sdmarc.net, mailto:dmarc@smtpeter.com
✓ Subdomain policy: reject #20

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

Report addresses in other domains have published their authorization.

DKIM

warn

Selectors: google

Found

Selectors: google
_domainkey: NOERROR

Selector	Key	Flags
google	RSA public key could not be parsed

Checks

✓ Keys found: google #7

DKIM keys found for this domain with selectors: google
!

Unreadable DKIM key

These keys could not be parsed, so signatures made with them will fail: google (RSA public key could not be parsed).

#23
✓ No problematic flags #24

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

DNSSEC

warn

Signed, DS published at parent

Found

DNSKEY records: Yes (3)
DS at parent: Yes
Algorithms: ECDSAP256SHA256 (13)
Key tags: 24639, 12087, 63930
Signatures valid until: 25 October 2026, 18:17 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 expire in 94h0m0s

DNSKEY signatures expire at 2026-10-25T18:17:29Z (in 94h0m0s). Check that re-signing works.

#21

MX

pass

5 mail servers

Found

Priority	Host	Records	Reverse DNS
10	aspmx.l.google.com	A 142.251.127.26 AAAA 2a00:1450:4001:c21::1a	lcfrai-in-f26.1e100.net ✓ lcfrai-in-f26.1e100.net ✓
20	alt1.aspmx.l.google.com	A 142.250.147.27 AAAA 2a00:1450:4025:c01::1a	rd-in-f27.1e100.net ✓ rd-in-f26.1e100.net ✓
20	alt2.aspmx.l.google.com	A 172.253.152.27 AAAA 2a00:1450:4010:c22::1a	yulpptr-in-f27.1e100.net ✓ yulpptr-in-f26.1e100.net ✓
30	aspmx2.googlemail.com	A 142.250.147.26 AAAA 2a00:1450:4025:c01::1a	rd-in-f26.1e100.net ✓ rd-in-f26.1e100.net ✓
30	aspmx3.googlemail.com	A 172.253.152.27 AAAA 2a00:1450:4010:c22::1a	yulpptr-in-f27.1e100.net ✓ yulpptr-in-f26.1e100.net ✓

Checks

✓ 5 MX records #9

Found 5 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.
✓ Redundant MX hosts #12

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

Found 5 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 10 MX addresss have a PTR record that resolves back to them.

TLS

warn

MTA-STS testing · TLS-RPT · DANE on 0 of 5 MX hosts

Found

MTA-STS record: v=STSv1; id=1763565706
Policy URL: https://mta-sts.bibliotheek.nl/.well-known/mta-sts.txt
Mode: testing
Allowed MX: aspmx.l.google.com, alt1.aspmx.l.google.com, alt2.aspmx.l.google.com, aspmx2.googlemail.com, aspmx3.googlemail.com
Max age: 604800 seconds
TLS-RPT record: v=TLSRPTv1; rua=mailto:reports@sendmarc.net

DANE (TLSA records)

MX host	TLSA	DNSSEC
aspmx.l.google.com	none	-
alt1.aspmx.l.google.com	none	-
alt2.aspmx.l.google.com	none	-
aspmx2.googlemail.com	none	-
aspmx3.googlemail.com	none	-

Checks

✓ Record published #32

MTA-STS record found with id 1763565706.
!

Policy in testing mode

With mode: testing, senders only report TLS problems (via TLS-RPT) and still deliver without TLS. Switch to mode: enforce once reports are clean.

#33
✓ All MX hosts covered #34

Every MX host matches an mx: line of the MTA-STS policy.
✓ Reports enabled #35

TLS reports are sent to: mailto:reports@sendmarc.net
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