tum.de

Checked 22 October 2026, 00:41 UTC · via 8.8.8.8
!Passed with warnings
25 passed 4 warnings 0 failed 2 info

SPF

info

SPF record published

Found

Record
v=spf1 a:mail.zv.tum.de a:mail.ze.tum.de redirect=_spf.mail.lrz.de
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).
  • i
    Delegated via redirect
    SPF record has no 'all' mechanism but redirects to _spf.mail.lrz.de, whose policy applies.
    #3
  • ✓ 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.tum.de)

Found

Record
v=DMARC1; p=quarantine; rua=mailto:dmarc-reports@lrz.de
Found at
_dmarc.tum.de
External report address
mailto:dmarc-reports@lrz.de (authorized)
TagValueMeaning
vDMARC1Version
pquarantinePolicy
ruamailto:dmarc-reports@lrz.deAggregate report addresses

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.
  • ✓ Aggregate reports enabled #19
    Aggregate reports are sent to: mailto:dmarc-reports@lrz.de
  • ✓ 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

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

pass

Signed, DS published at parent

Found

DNSKEY records
Yes (3)
DS at parent
Yes
Algorithms
RSASHA256 (8)
Key tags
6718, 43156, 14838
Signatures valid until
30 December 2026, 07:26 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 2026-12-30 #21
    DNSKEY signatures are valid until 2026-12-30T07:26:09Z.

MX

pass

2 mail servers

Found

PriorityHostRecordsReverse DNS
100postrelay1.lrz.deA 129.187.254.158 A 129.187.255.160 AAAA 2001:4ca0:0:103:0:25:1:1 AAAA 2001:4ca0:0:103::81bb:ffa0postrelay1a.lrz.de ✓ postrelay1b.lrz.de ✓ postrelay1a.lrz.de ✓ postrelay1.lrz.de ✓
100postrelay2.lrz.deA 129.187.254.159 A 129.187.255.161 AAAA 2001:4ca0:0:103:0:25:1:2 AAAA 2001:4ca0:0:103::81bb:ffa1postrelay2a.lrz.de ✓ postrelay2b.lrz.de ✓ postrelay2a.lrz.de ✓ postrelay2b.lrz.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.
  • ✓ 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 8 MX addresss have a PTR record that resolves back to them.

TLS

warn

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

Found

DANE (TLSA records)

MX hostTLSADNSSEC
postrelay1.lrz.de3 1 1 3d805975a26979f6…Yes
postrelay2.lrz.de3 1 1 aa00d3fd8f372d50…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 2 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