nkc.nl

Checked 22 October 2026, 14:42 UTC · via 8.8.8.8
!Passed with warnings
23 passed 5 warnings 0 failed 3 info

SPF

warn

SPF record published

Found

Record
v=spf1 a mx ip4:46.31.48.0/21 include:spf.protection.outlook.com ip6:2a01:111:f400::/48 ip6:2a01:111:f403::/48 ip4:40.92.0.0/15 ip4:40.107.0.0/16 ip4:52.100.0.0/14 ip4:104.47.0.0/17 ip4:194.109.148.128/26 ip4:90.145.27.170 ip4:87.249.123.155 ip4:50.31.63.44 ip4:205.201.128.0/20 ip4:205.201.128.0/20 ip4:198.2.128.0/18 include:spf.mandrillapp.com include:sendgrid.net include:fdspfeuc.freshemail.io ip4:185.136.64.128/27 ip4:185.136.65.128/27 ip4:199.255.192.0/22 ip4:199.127.232.0/22 ip4:54.240.0.0/18 ip4:69.169.224.0/20 ip4:23.249.208.0/20 ip4:23.251.224.0/19 ip4:76.223.176.0/20 ip4:54.240.64.0/19 ip4:54.240.96.0/19 ip4:52.82.172.0/22 include:spf.aon.net include:spf.mailjet.com -all
DNS lookups
10 of 10
Void lookups
0 of 2

Checks

  • ✓ No deprecated ptr mechanism #1
    No ptr mechanism found in SPF record.
  • ✓ 10 of 10 DNS lookups #2
    SPF record needs 10 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.
  • !
    Broad IP ranges
    These ranges authorize tens of thousands of addresses or more: ip4:40.92.0.0/15, ip4:52.100.0.0/14. Check that you really own and send from all of them.
    #27

DMARC

warn

p=reject (_dmarc.nkc.nl)

Found

Record
v=DMARC1; p=reject
Found at
_dmarc.nkc.nl
TagValueMeaning
vDMARC1Version
prejectPolicy

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.
  • !
    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
  • ✓ Subdomain policy: reject #20
    Subdomains are covered by policy 'reject'.

DKIM

pass

Selectors: selector1, selector2, s1, s2

Found

Selectors
selector1, selector2, s1, s2
_domainkey
NOERROR
SelectorKeyFlags
selector1RSA 2048 bits
selector2RSA 2048 bits
s1RSA 2048 bits
s2RSA 2048 bits

Checks

  • ✓ Keys found: selector1, selector2, s1, s2 #7
    DKIM keys found for this domain with selectors: selector1, selector2, s1, s2
  • ✓ Strong keys #23
    DKIM keys are strong enough: selector1: RSA 2048 bits; selector2: RSA 2048 bits; s1: RSA 2048 bits; s2: RSA 2048 bits.
  • ✓ No problematic flags #24
    No keys in test mode, revoked, or limited to SHA-1.

DNSSEC

warn

Not signed

Found

DNSKEY records
No (0)
DS at parent
No

Checks

  • !
    Not enabled
    DNSSEC is not enabled for this domain. Consider enabling DNSSEC to protect against DNS spoofing attacks.
    #8

MX

warn

1 mail server

Found

PriorityHostRecordsReverse DNS
0nkc-nl.mail.protection.outlook.comA 52.101.209.28 A 52.101.91.153 A 52.101.103.36 A 52.101.73.153 AAAA 2a01:111:f403:ca09::a AAAA 2a01:111:f403:ca21::c AAAA 2a01:111:f403:ca3c::6 AAAA 2a01:111:f403:ca21::8mail-cpjpr05cu00104.inbound.protection.outlook.com ✓ mail-matpr04cu00101.inbound.protection.outlook.com ✓ mail-miypr05cu00104.inbound.protection.outlook.com ✓ mail-as8pr05cu00401.inbound.protection.outlook.com ✓ mail-am7pr02cu00202.inbound.protection.outlook.com ✓ mail-matpr04cu00204.inbound.protection.outlook.com ✓ mail-zrxpr04cu00106.inbound.protection.outlook.com ✓ mail-matpr04cu00100.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 hostTLSADNSSEC
nkc-nl.mail.protection.outlook.comnone-

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