Mail domain report: zlto.nl

SPF

warn

SPF record published

Found

Record: v=spf1 include:spf.protection.outlook.com include:_spf.onlinespamfilter.nl ip4:5.255.75.0/24 include:spf.zlto.nl include:_spf.spotler.email include:spf.tribecrm.nl -all
DNS lookups: 6 of 10
Void lookups: 1 of 2
Problem: include:spf.zlto.nl does not exist or has no records

Checks

✓ No deprecated ptr mechanism #1

No ptr mechanism found in SPF record.
!

6 of 10 DNS lookups, with problems

SPF record needs 6 DNS lookups (limit is 10). Problems found: include:spf.zlto.nl does not exist or has no records.

#2
✓ 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.
!

1 void lookup

1 include/redirect target does not exist or has no records (limit is 2). This usually is a stale include; remove it.

#26
✓ No overly broad IP ranges #27

All ip4/ip6 ranges are narrow enough.

DMARC

warn

p=quarantine (_dmarc.zlto.nl)

Found

Record: v=DMARC1; p=quarantine; rua=mailto:dmarc_agg@vali.email; adkim=s; aspf=r;
Found at: _dmarc.zlto.nl
External report address: mailto:dmarc_agg@vali.email (authorized)

Tag	Value	Meaning
v	DMARC1	Version
p	quarantine	Policy
rua	mailto:dmarc_agg@vali.email	Aggregate report addresses
adkim	s	DKIM alignment (r = relaxed, s = strict)
aspf	r	SPF alignment (r = relaxed, s = strict)

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:dmarc_agg@vali.email
✓ 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

pass

Selectors: selector1, selector2

Found

Selectors: selector1, selector2
_domainkey: NOERROR

Selector	Key	Flags
selector1	RSA 2048 bits
selector2	RSA 2048 bits

Checks

✓ Keys found: selector1, selector2 #7

DKIM keys found for this domain with selectors: selector1, selector2
✓ Strong keys #23

DKIM keys are strong enough: selector1: RSA 2048 bits; selector2: RSA 2048 bits.
✓ 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: 23661
Signatures valid until: 5 November 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 2026-11-05 #21

DNSKEY signatures are valid until 2026-11-05T00:00:00Z.

MX

warn

1 mail server

Found

Priority	Host	Records	Reverse DNS
0	zlto-nl.mail.protection.outlook.com	A 52.101.181.153 A 52.101.68.15 A 52.101.68.12 A 52.101.103.140 AAAA 2a01:111:f403:ca04::a AAAA 2a01:111:f403:ca3c::a AAAA 2a01:111:f403:ca04::b AAAA 2a01:111:f403:ca48::e	mail-wa4pr04cu00101.inbound.protection.outlook.com ✓ mail-db6pr03cu00107.inbound.protection.outlook.com ✓ mail-db9pr02cu00204.inbound.protection.outlook.com ✓ mail-miypr02cu00204.inbound.protection.outlook.com ✓ mail-du0pr03cu00102.inbound.protection.outlook.com ✓ mail-zrxpr07cu00102.inbound.protection.outlook.com ✓ mail-dbbpr03cu00103.inbound.protection.outlook.com ✓ mail-miypr03cu00206.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
zlto-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