koeln-bonn-airport.de

Checked 21 October 2026, 23:10 UTC · via 8.8.8.8
!Passed with warnings
23 passed 6 warnings 0 failed 3 info

SPF

pass

SPF record published

Found

Record
v=spf1 a mx a:cgn-nebenan.de include:spf.protection.outlook.com include:_spf.cmail.ondemand.com ip4:194.110.25.161 ip4:194.110.25.162 ip4:194.110.25.163 ip4:52.157.149.216 ip4:35.242.247.107 ip4:34.107.8.58 ip4:34.107.88.2 ip4:35.246.224.53 -all
DNS lookups
6 of 10
Void lookups
0 of 2

Checks

  • ✓ No deprecated ptr mechanism #1
    No ptr mechanism found in SPF record.
  • ✓ 6 of 10 DNS lookups #2
    SPF record needs 6 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=quarantine (_dmarc.koeln-bonn-airport.de)

Found

Record
v=DMARC1;p=quarantine;ruf=mailto:drep@cgn.de;sp=quarantine;fo=1:d:s;adkim=r;aspf=r
Found at
_dmarc.koeln-bonn-airport.de
External report address
mailto:drep@cgn.de (not authorized)
TagValueMeaning
vDMARC1Version
pquarantinePolicy
spquarantineSubdomain policy
rufmailto:drep@cgn.deFailure report addresses
adkimrDKIM alignment (r = relaxed, s = strict)
aspfrSPF alignment (r = relaxed, s = strict)
fo1:d:sFailure reporting options

Checks

  • !
    Policy: quarantine
    DMARC policy is set to 'quarantine'. Consider upgrading to 'reject' for stronger protection once you've verified legitimate emails are passing authentication.
    #4
  • ✓ 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: quarantine #20
    Subdomains are covered by policy 'quarantine'.
  • !
    Report address not authorized
    These report addresses are in another domain that has not agreed to receive your reports, so receivers will not send them: mailto:drep@cgn.de (needs koeln-bonn-airport.de._report._dmarc.cgn.de). Ask the report provider to publish the record, or check the address.
    #29

DKIM

pass

Selectors: mail

Found

Selectors
mail
_domainkey
NOERROR
SelectorKeyFlags
mailRSA 2048 bits

Checks

  • ✓ Keys found: mail #7
    DKIM keys found for this domain with selectors: mail
  • ✓ Strong keys #23
    DKIM keys are strong enough: mail: RSA 2048 bits.
  • ✓ No problematic flags #24
    No keys in test mode, revoked, or limited to SHA-1.

DNSSEC

warn

Not signed

Found

DNSKEY records
No (0)
DS at parent
No

Checks

  • !
    Not enabled
    DNSSEC is not enabled for this domain. Consider enabling DNSSEC to protect against DNS spoofing attacks.
    #8

MX

warn

2 mail servers

Found

PriorityHostRecordsReverse DNS
20mail1.koeln-bonn-airport.deA 194.110.25.161mail1.koeln-bonn-airport.de ✓
20mail2.koeln-bonn-airport.deA 194.110.25.162mail2.koeln-bonn-airport.de ✓

Checks

  • ✓ 2 MX records #9
    Found 2 MX records for this domain.
  • ✓ All hosts resolve #10
    All MX records resolve to valid IP addresses.
  • !
    Hosts without IPv6
    The following MX hosts could not be resolved to IPv6 addresses: mail1.koeln-bonn-airport.de, mail2.koeln-bonn-airport.de
    #11
  • ✓ Redundant MX hosts #12
    Found 2 MX records, which provides redundancy for email delivery.
  • ✓ At most 5 MX records #13
    Found 2 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

warn

no MTA-STS · no TLS-RPT · DANE on 0 of 2 MX hosts

Found

DANE (TLSA records)

MX hostTLSADNSSEC
mail1.koeln-bonn-airport.denone-
mail2.koeln-bonn-airport.denone-

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