Mail domain report: flixbus.de

SPF

fail

SPF record published

Found

Record: v=spf1 mx include:spf.protection.outlook.com include:servers.mcsv.net ip4:213.239.254.0/24 ip4:213.203.239.0/26 include:amazonses.com include:spf.dynect.net include:mailgun.org include:spf.mailjet.com -all
DNS lookups: 11 of 10
Void lookups: 0 of 2

Checks

✓ No deprecated ptr mechanism #1

No ptr mechanism found in SPF record.
✗

11 DNS lookups, over the limit of 10

SPF record needs 11 DNS lookups (including nested includes), more than the limit of 10. Receivers will return a permerror; reduce includes or flatten the record.

#2
✓ 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

fail

p=none (_dmarc.flixbus.de)

Found

Record: v=DMARC1; p=none; pct=100; rua=mailto:re+tmpu8bn2p2c@dmarc.postmarkapp.com; sp=none;
Found at: _dmarc.flixbus.de
External report address: mailto:re+tmpu8bn2p2c@dmarc.postmarkapp.com (authorized)

Tag	Value	Meaning
v	DMARC1	Version
p	none	Policy
sp	none	Subdomain policy
pct	100	Percentage of mail the policy applies to
rua	mailto:re+tmpu8bn2p2c@dmarc.postmarkapp.com	Aggregate report addresses

Checks

✗

Policy: none (monitoring only)

DMARC policy is set to 'none', which only monitors but doesn't protect against spoofing. Consider upgrading to 'quarantine' or ideally 'reject'.

#4
✓ Record published #5

DMARC record exists for this domain.
✓ Valid syntax #17

DMARC record syntax is valid.
✓ Aggregate reports enabled #19

Aggregate reports are sent to: mailto:re+tmpu8bn2p2c@dmarc.postmarkapp.com
✓ External report addresses authorized #29

Report addresses in other domains have published their authorization.

DKIM

warn

Selectors: k1, selector1

Found

Selectors: k1, selector1
_domainkey: NOERROR

Selector	Key	Flags
k1	RSA 1024 bits
selector1	RSA 1024 bits

Checks

✓ Keys found: k1, selector1 #7

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

1024-bit DKIM key

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

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

pass

2 mail servers

Found

Priority	Host	Records	Reverse DNS
0	flixbus-de.mail.protection.outlook.com	A 52.101.73.126 A 52.101.68.12 A 52.101.68.10 A 52.101.103.162 AAAA 2a01:111:f403:ca09::24 AAAA 2a01:111:f403:ca48::e AAAA 2a01:111:f403:c967::c AAAA 2a01:111:f403:ca21::c	mail-am8pr83cu00106.inbound.protection.outlook.com ✓ mail-db9pr02cu00204.inbound.protection.outlook.com ✓ mail-dbbpr03cu00102.inbound.protection.outlook.com ✓ mail-miypr03cu00202.inbound.protection.outlook.com ✓ mail-am6pr02cu00204.inbound.protection.outlook.com ✓ mail-miypr03cu00206.inbound.protection.outlook.com ✓ mail-cpjpr05cu00204.inbound.protection.outlook.com ✓ mail-matpr04cu00204.inbound.protection.outlook.com ✓
1	flixbus-de.mail.eo.outlook.com	A 52.101.209.153 A 52.101.91.21 A 52.101.103.143 A 52.101.181.153 AAAA 2a01:111:f403:ca38::8 AAAA 2a01:111:f403:ca38::a AAAA 2a01:111:f403:ca04::c AAAA 2a01:111:f403:ca3c::6	mail-cpjpr04cu00101.inbound.protection.outlook.com ✓ mail-matpr05cu00105.inbound.protection.outlook.com ✓ mail-miypr03cu00107.inbound.protection.outlook.com ✓ mail-wa4pr04cu00101.inbound.protection.outlook.com ✓ mail-wa4pr04cu00100.inbound.protection.outlook.com ✓ mail-wa4pr05cu00102.inbound.protection.outlook.com ✓ mail-db9pr02cu00204.inbound.protection.outlook.com ✓ mail-zrxpr04cu00106.inbound.protection.outlook.com ✓

Checks

✓ 2 MX records #9

Found 2 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.
✓ 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 16 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 host	TLSA	DNSSEC
flixbus-de.mail.protection.outlook.com	none	-
flixbus-de.mail.eo.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