Mail domain report: corendon.nl

SPF

pass

SPF record published

Found

Record: v=spf1 include:_spf.corendon.nl include:sg.corendon.nl include:trustpilotservice.com include:spf.protection.outlook.com include:ogone.corendon.nl include:spf.afas.online include:_spf.salesforce.com include:_spf.trustit.eu ~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

fail

p=none (_dmarc.corendon.nl)

Found

Record: v=DMARC1; p=none; pct=100; aspf=r; adkim=r; rua=mailto:dmarc_monitor@corendon.nl; ruf=mailto:dmarc_forensic@corendon.nl; fo=1:s
Found at: _dmarc.corendon.nl

Tag	Value	Meaning
v	DMARC1	Version
p	none	Policy
pct	100	Percentage of mail the policy applies to
rua	mailto:dmarc_monitor@corendon.nl	Aggregate report addresses
ruf	mailto:dmarc_forensic@corendon.nl	Failure report addresses
adkim	r	DKIM alignment (r = relaxed, s = strict)
aspf	r	SPF alignment (r = relaxed, s = strict)
fo	1:s	Failure reporting options

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.
✓ Aggregate reports enabled #19

Aggregate reports are sent to: mailto:dmarc_monitor@corendon.nl
✓ Report addresses in own domain #29

All report addresses are in your own organizational domain.

DKIM

warn

Selectors: mail, selector1, s1, s2

Found

Selectors: mail, selector1, s1, s2
_domainkey: NOERROR

Selector	Key	Flags
mail	RSA 2048 bits	h=sha256
selector1	RSA 1024 bits
s1	RSA 2048 bits
s2	RSA 1024 bits

Checks

✓ Keys found: mail, selector1, s1, s2 #7

DKIM keys found for this domain with selectors: mail, selector1, s1, s2
!

1024-bit DKIM key

1024-bit RSA keys are the minimum and are considered weak today: selector1 (1024 bits), s2 (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 (3)
DS at parent: Yes
Algorithms: ECDSAP256SHA256 (13)
Key tags: 52181, 36012, 50081
Signatures valid until: 20 December 2026, 13:00 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 2026-12-20 #21

DNSKEY signatures are valid until 2026-12-20T13:00:39Z.

MX

warn

1 mail server

Found

Priority	Host	Records	Reverse DNS
8	corendon-nl.mail.protection.outlook.com	A 52.101.68.15 A 52.101.103.140 A 52.101.91.156 A 52.101.73.155 AAAA 2a01:111:f403:ca38::8 AAAA 2a01:111:f403:ca48::8 AAAA 2a01:111:f403:ca38::a AAAA 2a01:111:f403:ca04::c	mail-db6pr03cu00107.inbound.protection.outlook.com ✓ mail-miypr02cu00204.inbound.protection.outlook.com ✓ mail-maspr04cu00104.inbound.protection.outlook.com ✓ mail-am7pr02cu00203.inbound.protection.outlook.com ✓ mail-wa4pr04cu00100.inbound.protection.outlook.com ✓ mail-miypr02cu00100.inbound.protection.outlook.com ✓ mail-wa4pr05cu00102.inbound.protection.outlook.com ✓ mail-db9pr02cu00204.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
corendon-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