lehrer-online.de

Checked 21 October 2026, 23:11 UTC · via 8.8.8.8
✗Problems found
17 passed 6 warnings 1 failed 3 info

SPF

warn

SPF record published

Found

Record
v=spf1 a mx ptr ip4:89.191.78.0/24 ip4:82.165.112.33 include:spf.protection.outlook.com include:spf.crsend.com ip4:185.98.184.0/24 ip4:80.82.206.0/26 ip4:188.40.30.118 include:emsd1.com include:_spf.sendnode.com ~all
DNS lookups
7 of 10
Void lookups
0 of 2

Checks

  • !
    Uses deprecated ptr mechanism
    The ptr mechanism in SPF records is deprecated due to performance issues and should be avoided.
    #1
  • ✓ 7 of 10 DNS lookups #2
    SPF record needs 7 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

fail

p=none (_dmarc.lehrer-online.de)

Found

Record
v=DMARC1;p=none;
Found at
_dmarc.lehrer-online.de
TagValueMeaning
vDMARC1Version
pnonePolicy

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.
  • !
    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

DKIM

warn

No keys found under the checked selectors

Found

Selectors
None found
_domainkey
NOERROR

Checks

  • !
    No key under common selectors
    The _domainkey name exists but no DKIM key was found under the common selectors. Selectors are provider-specific; check yours with -selector.
    #7

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

1 mail server

Found

PriorityHostRecordsReverse DNS
10lehreronline-de01e.mail.protection.outlook.comA 52.101.73.145 A 52.101.103.143 A 52.101.68.25 A 52.101.103.162 AAAA 2a01:111:f403:ca21::e AAAA 2a01:111:f403:ca04::4 AAAA 2a01:111:f403:ca09::26 AAAA 2a01:111:f403:ca04::cmail-am6pr02cu00301.inbound.protection.outlook.com ✓ mail-miypr03cu00107.inbound.protection.outlook.com ✓ mail-db8pr02cu00101.inbound.protection.outlook.com ✓ mail-miypr03cu00202.inbound.protection.outlook.com ✓ mail-matpr04cu00306.inbound.protection.outlook.com ✓ mail-db4pr02cu00204.inbound.protection.outlook.com ✓ mail-am8pr83cu00106.inbound.protection.outlook.com ✓ mail-db9pr02cu00204.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 hostTLSADNSSEC
lehreronline-de01e.mail.protection.outlook.comnone-

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