nlnetlabs.nl

Checked 21 October 2026, 21:23 UTC · via 8.8.8.8
✗Problems found
24 passed 5 warnings 1 failed 1 info

SPF

warn

SPF record published

Found

Record
v=spf1 +a include:_spf.google.com include:mailbox.org ip4:185.49.140.0/22 ip6:2a04:b900::/29 ~all
DNS lookups
4 of 10
Void lookups
0 of 2

Checks

  • ✓ No deprecated ptr mechanism #1
    No ptr mechanism found in SPF record.
  • ✓ 4 of 10 DNS lookups #2
    SPF record needs 4 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: ip6:2a04:b900::/29. Check that you really own and send from all of them.
    #27

DMARC

fail

p=none (_dmarc.nlnetlabs.nl)

Found

Record
v=DMARC1; p=none; sp=none; psd=n; rua=mailto:dmarc-feedback@nlnetlabs.nl
Found at
_dmarc.nlnetlabs.nl
TagValueMeaning
vDMARC1Version
pnonePolicy
spnoneSubdomain policy
ruamailto:dmarc-feedback@nlnetlabs.nlAggregate report addresses
psdn

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-feedback@nlnetlabs.nl
  • ✓ Report addresses in own domain #29
    All report addresses are in your own organizational domain.

DKIM

warn

Selectors: default, google

Found

Selectors
default, google
_domainkey
NOERROR
SelectorKeyFlags
defaultRSA 1024 bitstest mode (t=y)
googleRSA 2048 bits

Checks

  • ✓ Keys found: default, google #7
    DKIM keys found for this domain with selectors: default, google
  • !
    1024-bit DKIM key
    1024-bit RSA keys are the minimum and are considered weak today: default (1024 bits). Rotate to a 2048-bit key.
    #23
  • !
    Key in test mode
    These keys have t=y, so receivers treat DKIM failures as a test: default. Remove t=y once DKIM works.
    #24

DNSSEC

pass

Signed, DS published at parent

Found

DNSKEY records
Yes (2)
DS at parent
Yes
Algorithms
RSASHA256 (8)
Key tags
50602, 42393
Signatures valid until
13 November 2026, 08:45 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 2026-11-13 #21
    DNSKEY signatures are valid until 2026-11-13T08:45:36Z.

MX

pass

4 mail servers

Found

PriorityHostRecordsReverse DNS
10mxext1.mailbox.orgA 80.241.60.212 AAAA 2001:67c:2050:104:0:1:25:1mx1.mailbox.org ✓ mx1.mailbox.org ✓
10mxext2.mailbox.orgA 80.241.60.215 AAAA 2001:67c:2050:104:0:2:25:1mx2.mailbox.org ✓ mx2.mailbox.org ✓
10mxext3.mailbox.orgA 80.241.60.216 AAAA 2001:67c:2050:104:0:3:25:1mx3.mailbox.org ✓ mx3.mailbox.org ✓
10mxext4.mailbox.orgA 80.241.60.217 AAAA 2001:67c:2050:104:0:4:25:1mx4.mailbox.org ✓ mx4.mailbox.org ✓

Checks

  • ✓ 4 MX records #9
    Found 4 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.
  • ✓ Redundant MX hosts #12
    Found 4 MX records, which provides redundancy for email delivery.
  • ✓ At most 5 MX records #13
    Found 4 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 4 of 4 MX hosts

Found

DANE (TLSA records)

MX hostTLSADNSSEC
mxext1.mailbox.org3 1 1 4758af6f02dfb5dc… 3 1 1 e41cc7633029afdb… 3 1 1 996ad31d65e03f03…Yes
mxext2.mailbox.org3 1 1 4758af6f02dfb5dc… 3 1 1 e41cc7633029afdb… 3 1 1 996ad31d65e03f03…Yes
mxext3.mailbox.org3 1 1 996ad31d65e03f03… 3 1 1 4758af6f02dfb5dc… 3 1 1 e41cc7633029afdb…Yes
mxext4.mailbox.org3 1 1 996ad31d65e03f03… 3 1 1 e41cc7633029afdb… 3 1 1 4758af6f02dfb5dc…Yes

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
  • !
    Not configured
    MTA-STS or DANE is used without TLS-RPT, so you get no reports when senders fail to deliver because of TLS problems. Publish _smtp._tls TXT "v=TLSRPTv1; rua=mailto:...".
    #35
  • ✓ DANE on all MX hosts #36
    All 4 MX hosts publish DNSSEC-validated TLSA records.

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