Mail domain report: guestoo.de

SPF

pass

SPF record published

Found

Record: v=spf1 include:spf.codepiraten.com -all
DNS lookups: 1 of 10
Void lookups: 0 of 2

Checks

✓ No deprecated ptr mechanism #1

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

SPF record needs 1 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.guestoo.de)

Found

Record: v=DMARC1; p=reject; sp=quarantine; rua=mailto:mail-reports@codepiraten.com
Found at: _dmarc.guestoo.de
External report address: mailto:mail-reports@codepiraten.com (authorized)

Tag	Value	Meaning
v	DMARC1	Version
p	reject	Policy
sp	quarantine	Subdomain policy
rua	mailto:mail-reports@codepiraten.com	Aggregate 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:mail-reports@codepiraten.com
✓ Subdomain policy: quarantine #20

Subdomains are covered by policy 'quarantine'.
✓ External report addresses authorized #29

Report addresses in other domains have published their authorization.

DKIM

warn

Selectors: mail

Found

Selectors: mail
_domainkey: NOERROR

Selector	Key	Flags
mail	RSA 1024 bits

Checks

✓ Keys found: mail #7

DKIM keys found for this domain with selectors: mail
!

1024-bit DKIM key

1024-bit RSA keys are the minimum and are considered weak today: mail (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 (1)
DS at parent: Yes
Algorithms: ECDSAP256SHA256 (13)
Key tags: 35922
Signatures valid until: 29 October 2026, 00:00 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 2026-10-29 #21

DNSKEY signatures are valid until 2026-10-29T00:00:00Z.

MX

warn

1 mail server

Found

Priority	Host	Records	Reverse DNS
10	mailit.app	A 94.130.150.95 AAAA 2a01:4f8:c0c:3f49::2	mailit.app ✓ mail01.mailit.app ✓

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 2 MX addresss have a PTR record that resolves back to them.

TLS

pass

MTA-STS enforce · TLS-RPT · DANE on 1 of 1 MX hosts

Found

MTA-STS record: v=STSv1; id=20260923140000Z
Policy URL: https://mta-sts.guestoo.de/.well-known/mta-sts.txt
Mode: enforce
Allowed MX: mailit.app, mail03.mailit.app
Max age: 15552000 seconds
TLS-RPT record: v=TLSRPTv1; rua=mailto:mail-reports@codepiraten.com

DANE (TLSA records)

MX host	TLSA	DNSSEC
mailit.app	3 1 1 b1b20b9e711a8551…	Yes

Checks

✓ Record published #32

MTA-STS record found with id 20260923140000Z.
✓ Policy enforced #33

The MTA-STS policy is enforced and cached for 4320h0m0s.
✓ All MX hosts covered #34

Every MX host matches an mx: line of the MTA-STS policy.
✓ Reports enabled #35

TLS reports are sent to: mailto:mail-reports@codepiraten.com
✓ 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