dsmz.de

Checked 21 October 2026, 22:15 UTC · via 8.8.8.8
✗Problems found
24 passed 4 warnings 1 failed 1 info

SPF

pass

SPF record published

Found

Record
v=spf1 include:spf.mailsupport.dfn.de a:mail.dsmz.de a:mailserver.dsmz.de ~all
DNS lookups
3 of 10
Void lookups
0 of 2

Checks

  • ✓ No deprecated ptr mechanism #1
    No ptr mechanism found in SPF record.
  • ✓ 3 of 10 DNS lookups #2
    SPF record needs 3 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.dsmz.de)

Found

Record
v=DMARC1; p=none; sp=none; adkim=s; aspf=r; pct=100;\010rf=afrf; rua=mailto:dmarc-rua@dsmz.de
Found at
_dmarc.dsmz.de
TagValueMeaning
vDMARC1Version
pnonePolicy
spnoneSubdomain policy
pct100Percentage of mail the policy applies to
ruamailto:dmarc-rua@dsmz.deAggregate report addresses
adkimsDKIM alignment (r = relaxed, s = strict)
aspfrSPF alignment (r = relaxed, s = strict)
\010rfafrf

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:dmarc-rua@dsmz.de
  • ✓ Report addresses in own domain #29
    All report addresses are in your own organizational domain.

DKIM

warn

Selectors: s1

Found

Selectors
s1
_domainkey
NOERROR
SelectorKeyFlags
s1RSA 1024 bits

Checks

  • ✓ Keys found: s1 #7
    DKIM keys found for this domain with selectors: s1
  • !
    1024-bit DKIM key
    1024-bit RSA keys are the minimum and are considered weak today: s1 (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

3 mail servers

Found

PriorityHostRecordsReverse DNS
10a1641.mx.srv.dfn.deA 194.95.232.103 AAAA 2001:638:d:c301:acdc:1979:2:47a1641.mx.srv.dfn.de ✓ a1641.mx.srv.dfn.de ✓
10b1641.mx.srv.dfn.deA 194.95.234.103 AAAA 2001:638:d:c302:acdc:1979:2:47b1641.mx.srv.dfn.de ✓ b1641.mx.srv.dfn.de ✓
10c1641.mx.srv.dfn.deA 194.95.238.103 AAAA 2001:638:d:c303:acdc:1979:2:47c1641.mx.srv.dfn.de ✓ c1641.mx.srv.dfn.de ✓

Checks

  • ✓ 3 MX records #9
    Found 3 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 3 MX records, which provides redundancy for email delivery.
  • ✓ At most 5 MX records #13
    Found 3 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 6 MX addresss have a PTR record that resolves back to them.

TLS

warn

no MTA-STS · no TLS-RPT · DANE on 3 of 3 MX hosts

Found

DANE (TLSA records)

MX hostTLSADNSSEC
a1641.mx.srv.dfn.de3 0 1 9bec67f55f2afdb7…Yes
b1641.mx.srv.dfn.de3 0 1 9bec67f55f2afdb7…Yes
c1641.mx.srv.dfn.de3 0 1 9bec67f55f2afdb7…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 3 MX hosts 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