Mail domain report: erasmusmc.nl

SPF

pass

SPF record published

Found

Record: v=spf1 ip4:156.83.10.0/24 ip4:194.158.15.2/25 include:spfext.erasmusmc.nl include:spfext2.erasmusmc.nl ip4:35.177.224.195 ip4:52.77.71.183 ip4:83.149.98.72 ip4:212.204.201.35 include:spf.protection.outlook.com include:_spf.zorgmail.nl -all
DNS lookups: 9 of 10
Void lookups: 0 of 2

Checks

✓ No deprecated ptr mechanism #1

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

SPF record needs 9 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

warn

p=reject (_dmarc.erasmusmc.nl)

Found

Record: v=DMARC1;p=reject
Found at: _dmarc.erasmusmc.nl

Tag	Value	Meaning
v	DMARC1	Version
p	reject	Policy

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

warn

Selectors: k1, selector1, selector2, s1, s2

Found

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

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

Checks

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

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

1024-bit DKIM key

1024-bit RSA keys are the minimum and are considered weak today: k1 (1024 bits), selector2 (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

pass

Signed, DS published at parent

Found

DNSKEY records: Yes (5)
DS at parent: Yes
Algorithms: ECDSAP256SHA256 (13)
Key tags: 43017, 60816, 28341, 21273, 2172
Signatures valid until: 12 November 2026, 01:28 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 2026-11-12 #21

DNSKEY signatures are valid until 2026-11-12T01:28:11Z.

MX

warn

1 mail server

Found

Priority	Host	Records	Reverse DNS
10	erasmusmc-nl.k-v1.mx.microsoft	A 52.101.73.123 A 52.101.68.8 A 52.101.73.155 A 52.101.103.143 AAAA 2a01:111:f403:ca21::e AAAA 2a01:111:f403:ca04::10 AAAA 2a01:111:f403:ca09::26 AAAA 2a01:111:f403:ca04::9	mail-am6pr02cu00203.inbound.protection.outlook.com ✓ mail-du0pr03cu00100.inbound.protection.outlook.com ✓ mail-am7pr02cu00203.inbound.protection.outlook.com ✓ mail-miypr03cu00107.inbound.protection.outlook.com ✓ mail-matpr04cu00306.inbound.protection.outlook.com ✓ mail-dbapr03cu00100.inbound.protection.outlook.com ✓ mail-am8pr83cu00106.inbound.protection.outlook.com ✓ mail-db7pr03cu00601.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 1 of 1 MX hosts

Found

DANE (TLSA records)

MX host	TLSA	DNSSEC
erasmusmc-nl.k-v1.mx.microsoft	2 0 1 c1ad7778796d20bc… 3 1 1 803f7447cc75b208… 3 1 1 cfd68bde4129c00a… 3 1 1 54883cc5f1849331… 2 0 1 ea7a25255d111fc3…	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 1 MX host 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