tue.nl

Checked 21 October 2026, 21:26 UTC · via 8.8.8.8
!Passed with warnings
26 passed 4 warnings 0 failed 3 info

SPF

pass

SPF record published

Found

Record
v=spf1 ip4:167.89.63.218 ip4:185.138.80.117 include:spfdefault.mail.tue.nl include:spf.topdesk.net include:smtpeter.com include:spf.interconnect.nl include:carerix.net a:outmail.hireserve.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

pass

p=reject (_dmarc.tue.nl)

Found

Record
v=DMARC1; p=reject; sp=reject; rua=mailto:dmarc@xw3qj0xq.uriports.com; fo=1:d:s
Found at
_dmarc.tue.nl
External report address
mailto:dmarc@xw3qj0xq.uriports.com (authorized)
TagValueMeaning
vDMARC1Version
prejectPolicy
sprejectSubdomain policy
ruamailto:dmarc@xw3qj0xq.uriports.comAggregate report addresses
fo1:d:sFailure reporting options

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.
  • ✓ Aggregate reports enabled #19
    Aggregate reports are sent to: mailto:dmarc@xw3qj0xq.uriports.com
  • ✓ Subdomain policy: reject #20
    Subdomains are covered by policy 'reject'.
  • ✓ External report addresses authorized #29
    Report addresses in other domains have published their authorization.

DKIM

warn

Selectors: selector1

Found

Selectors
selector1
_domainkey
NOERROR
SelectorKeyFlags
selector1RSA 1024 bits

Checks

  • ✓ Keys found: selector1 #7
    DKIM keys found for this domain with selectors: selector1
  • !
    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

warn

Signed, DS published at parent

Found

DNSKEY records
Yes (4)
DS at parent
Yes
Algorithms
RSASHA256 (8)
Key tags
60901, 37209, 61611, 16415
Signatures valid until
25 October 2026, 06:48 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 expire in 81h0m0s
    DNSKEY signatures expire at 2026-10-25T06:48:33Z (in 81h0m0s). Check that re-signing works.
    #21

MX

warn

1 mail server

Found

PriorityHostRecordsReverse DNS
10tue-nl.mail.protection.outlook.comA 52.101.185.24 A 52.101.68.8 A 52.101.209.28 A 52.101.73.145 AAAA 2a01:111:f403:ca21::e AAAA 2a01:111:f403:ca04::d AAAA 2a01:111:f403:ca48::e AAAA 2a01:111:f403:ca21::8mail-zrxpr07cu00100.inbound.protection.outlook.com ✓ mail-du0pr03cu00100.inbound.protection.outlook.com ✓ mail-cpjpr05cu00104.inbound.protection.outlook.com ✓ mail-am6pr02cu00301.inbound.protection.outlook.com ✓ mail-matpr04cu00306.inbound.protection.outlook.com ✓ mail-db6pr03cu00105.inbound.protection.outlook.com ✓ mail-miypr03cu00206.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
tue-nl.mail.protection.outlook.comnone-
Lookup error: DNS query for _smtp._tls.tue.nl failed: read udp 46.225.38.91:54148->8.8.8.8:53: i/o timeout

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
    Could not be checked
    The TLS-RPT lookup failed, so this could not be checked: DNS query for _smtp._tls.tue.nl failed: read udp 46.225.38.91:54148->8.8.8.8:53: i/o timeout
    #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