Mail domain report: isso.nl

SPF

pass

SPF record published

Found

Record: v=spf1 a mx ip4:158.120.84.56 ip4:23.97.219.0 ip4:145.128.233.130 ip4:213.132.210.49 ip4:149.72.38.29 ip4:40.68.168.67 ip4:95.211.51.216 ip4:20.224.68.105 include:_spf.fluxility.com include:sendgrid.net include:spf.flowmailer.net include:spf.protection.outlook.com include:_spf.exonet.nl -all
DNS lookups: 8 of 10
Void lookups: 0 of 2

Checks

✓ No deprecated ptr mechanism #1

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

SPF record needs 8 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.isso.nl)

Found

Record: v=DMARC1; p=none;
Found at: _dmarc.isso.nl

Tag	Value	Meaning
v	DMARC1	Version
p	none	Policy

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.
!

No aggregate reports (rua)

DMARC record has no rua tag, so you receive no aggregate reports about who sends mail as your domain. Add rua=mailto:...

#19

DKIM

warn

Selectors: selector1, selector2, s1, s2

Found

Selectors: selector1, selector2, s1, s2
_domainkey: NOERROR

Selector	Key	Flags
selector1	RSA 1024 bits
selector2	RSA 2048 bits
s1	RSA 2048 bits
s2	RSA 2048 bits

Checks

✓ Keys found: selector1, selector2, s1, s2 #7

DKIM keys found for this domain with selectors: selector1, selector2, s1, s2
!

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 (2)
DS at parent: Yes
Algorithms: RSASHA256 (8)
Key tags: 20482, 6831
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	isso-nl.mail.protection.outlook.com	A 52.101.185.21 A 52.101.68.27 A 52.101.91.162 A 52.101.103.137 AAAA 2a01:111:f403:ca21::8 AAAA 2a01:111:f403:ca04::e AAAA 2a01:111:f403:ca48::12 AAAA 2a01:111:f403:ca48::8	mail-zrxpr05cu00105.inbound.protection.outlook.com ✓ mail-db7pr03cu00503.inbound.protection.outlook.com ✓ mail-matpr04cu00302.inbound.protection.outlook.com ✓ mail-miypr02cu00101.inbound.protection.outlook.com ✓ mail-matpr04cu00100.inbound.protection.outlook.com ✓ mail-db8pr02cu00106.inbound.protection.outlook.com ✓ mail-miypr05cu00202.inbound.protection.outlook.com ✓ mail-miypr02cu00100.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
isso-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