Mail domain report: tudelft.nl

SPF

pass

SPF record published

Found

Record: v=spf1 ip4:130.161.131.0/24 ip4:131.180.77.44 ip4:52.59.111.152 include:spf.protection.outlook.com ip4:46.31.188.52 ip4:212.83.209.198 ip4:212.83.209.204 include:spf.afas.online ip4:94.143.211.206 ip4:94.143.211.207 include:spf.recruitmail.com ip4:46.31.48.0/21 include:spf.topdesk.net include:spf.faqtory.nl include:a._spf.brightspace.com ip4:136.144.199.28 ip4:136.144.226.32 ip4:77.74.54.216 ip4:213.206.232.0/27 ip4:185.136.64.128/27 ip4:185.136.65.128/27 include:spf-x-tudelft-nl.dataduiker.app ~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.tudelft.nl)

Found

Record: v=DMARC1; p=reject; rua=mailto:dmarc-reports@tudelft.nl; ruf=mailto:dmarc-reports@tudelft.nl
Found at: _dmarc.tudelft.nl

Tag	Value	Meaning
v	DMARC1	Version
p	reject	Policy
rua	mailto:dmarc-reports@tudelft.nl	Aggregate report addresses
ruf	mailto:dmarc-reports@tudelft.nl	Failure report addresses

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-reports@tudelft.nl
✓ Subdomain policy: reject #20

Subdomains are covered by policy 'reject'.
✓ Report addresses in own domain #29

All report addresses are in your own organizational domain.

DKIM

warn

Selectors: mail, k1, selector1, selector2, s1, s2

Found

Selectors: mail, k1, selector1, selector2, s1, s2
_domainkey: NOERROR

Selector	Key	Flags
mail	RSA 1024 bits
k1	RSA 1024 bits
selector1	RSA 2048 bits
selector2	RSA 2048 bits
s1	RSA 2048 bits
s2	RSA 1024 bits

Checks

✓ Keys found: mail, k1, selector1, selector2, s1, s2 #7

DKIM keys found for this domain with selectors: mail, k1, selector1, selector2, s1, s2
!

1024-bit DKIM key

1024-bit RSA keys are the minimum and are considered weak today: mail (1024 bits), k1 (1024 bits), s2 (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 (3)
DS at parent: Yes
Algorithms: RSASHA256 (8)
Key tags: 14343, 26510, 35380
Signatures valid until: 25 October 2026, 01:11 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 76h0m0s

DNSKEY signatures expire at 2026-10-25T01:11:17Z (in 76h0m0s). Check that re-signing works.

#21

MX

warn

1 mail server

Found

Priority	Host	Records	Reverse DNS
10	tudelft-nl.mail.protection.outlook.com	A 52.101.103.140 A 52.101.185.114 A 52.101.68.29 A 52.101.73.145 AAAA 2a01:111:f403:ca38::8 AAAA 2a01:111:f403:ca48::c AAAA 2a01:111:f403:ca48::8 AAAA 2a01:111:f403:ca48::12	mail-miypr02cu00204.inbound.protection.outlook.com ✓ mail-zrxpr04cu00102.inbound.protection.outlook.com ✓ mail-dbapr03cu00105.inbound.protection.outlook.com ✓ mail-am6pr02cu00301.inbound.protection.outlook.com ✓ mail-wa4pr04cu00100.inbound.protection.outlook.com ✓ mail-miypr03cu00104.inbound.protection.outlook.com ✓ mail-miypr02cu00100.inbound.protection.outlook.com ✓ mail-miypr05cu00202.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
tudelft-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