Mail domain report: astron.nl

SPF

pass

SPF record published

Found

Record: v=spf1 include:c05aw084hi.powerspf.com ~all
DNS lookups: 2 of 10
Void lookups: 0 of 2

Checks

✓ No deprecated ptr mechanism #1

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

SPF record needs 2 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=reject (_dmarc.astron.nl)

Found

Record: v=DMARC1; p=reject; sp=none; rua=mailto:8xyzadw5yr@rua.powerdmarc.com; ruf=mailto:8xyzadw5yr@ruf.powerdmarc.com; fo=1; t=n;
Found at: _dmarc.astron.nl
External report address: mailto:8xyzadw5yr@rua.powerdmarc.com (authorized)
External report address: mailto:8xyzadw5yr@ruf.powerdmarc.com (authorized)

Tag	Value	Meaning
v	DMARC1	Version
p	reject	Policy
sp	none	Subdomain policy
rua	mailto:8xyzadw5yr@rua.powerdmarc.com	Aggregate report addresses
ruf	mailto:8xyzadw5yr@ruf.powerdmarc.com	Failure report addresses
fo	1	Failure reporting options
t	n

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:8xyzadw5yr@rua.powerdmarc.com
!

Subdomains unprotected (sp=none)

DMARC subdomain policy is sp=none, so spoofed mail from subdomains is not blocked. Consider sp=quarantine or sp=reject.

#20
✓ External report addresses authorized #29

Report addresses in other domains have published their authorization.

DKIM

warn

Selectors: selector1, selector2

Found

Selectors: selector1, selector2
_domainkey: NOERROR

Selector	Key	Flags
selector1	RSA 1024 bits
selector2	RSA 2048 bits

Checks

✓ Keys found: selector1, selector2 #7

DKIM keys found for this domain with selectors: selector1, selector2
!

1024-bit DKIM key

1024-bit RSA keys are the minimum and are considered weak today: selector1 (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: 8201
Signatures valid until: 3 November 2026, 17:02 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 2026-11-03 #21

DNSKEY signatures are valid until 2026-11-03T17:02:43Z.

MX

warn

1 mail server

Found

Priority	Host	Records	Reverse DNS
0	astron-nl.mail.protection.outlook.com	A 52.101.68.39 A 52.101.103.162 A 52.101.209.153 A 52.101.73.120 AAAA 2a01:111:f403:ca09::22 AAAA 2a01:111:f403:ca04::c AAAA 2a01:111:f403:ca21::10 AAAA 2a01:111:f403:ca04::f	mail-db7pr03cu00607.inbound.protection.outlook.com ✓ mail-miypr03cu00202.inbound.protection.outlook.com ✓ mail-cpjpr04cu00101.inbound.protection.outlook.com ✓ mail-am7pr02cu00300.inbound.protection.outlook.com ✓ mail-am7pr02cu00302.inbound.protection.outlook.com ✓ mail-db9pr02cu00204.inbound.protection.outlook.com ✓ mail-matpr05cu00100.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

info

MTA-STS enforce · TLS-RPT · DANE on 0 of 1 MX hosts

Found

MTA-STS record: v=STSv1; id=20240316082909795848;
Policy URL: https://mta-sts.astron.nl/.well-known/mta-sts.txt
Mode: enforce
Allowed MX: astron-nl.mail.protection.outlook.com
Max age: 86400 seconds
TLS-RPT record: v=TLSRPTv1;rua=mailto:8xyzadw5yr@tls.powerdmarc.com

DANE (TLSA records)

MX host	TLSA	DNSSEC
astron-nl.mail.protection.outlook.com	none	-

Checks

✓ Record published #32

MTA-STS record found with id 20240316082909795848.
✓ Policy enforced #33

The MTA-STS policy is enforced and cached for 24h0m0s.
✓ 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:8xyzadw5yr@tls.powerdmarc.com
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