ism.de

SPF record published

Found

Record

v=spf1 a:ism.de mx:smtp.ism.de ip4:195.52.126.157 include:_spf-eu.ionos.com include:9158016.spf04.hubspotemail.net include:sxb1nlsmtp01.prod.sxb1.secureserver.net ~all

DNS lookups

5 of 10

Void lookups

1 of 2

Problem

include:sxb1nlsmtp01.prod.sxb1.secureserver.net does not exist or has no records

Checks

• ✓ No deprecated ptr mechanism #1

  No ptr mechanism found in SPF record.
• !

  5 of 10 DNS lookups, with problems

  SPF record needs 5 DNS lookups (limit is 10). Problems found: include:sxb1nlsmtp01.prod.sxb1.secureserver.net does not exist or has no records.

  #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.
• !

  1 void lookup

  1 include/redirect target does not exist or has no records (limit is 2). This usually is a stale include; remove it.

  #26
• ✓ No overly broad IP ranges #27

  All ip4/ip6 ranges are narrow enough.

p=quarantine (_dmarc.ism.de)

Found

Record

v=DMARC1; p=quarantine; sp=none; rua=mailto:klaus.hess@ism.de; ruf=mailto:Klaus.Hess@ism.de; rf=afrf; pct=100; ri=86400

Found at

_dmarc.ism.de

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:klaus.hess@ism.de
• !

  Subdomains unprotected (sp=none)

  DMARC subdomain policy is sp=none, so spoofed mail from subdomains is not blocked. Consider sp=quarantine or sp=reject.

  #20
• ✓ Report addresses in own domain #29

  All report addresses are in your own organizational domain.

Selectors: default, mail, google

Found

Selectors

default, mail, google

_domainkey

NOERROR

Checks

• ✓ Keys found: default, mail, google #7

  DKIM keys found for this domain with selectors: default, mail, google
• !

  1024-bit DKIM key

  1024-bit RSA keys are the minimum and are considered weak today: default (1024 bits), mail (1024 bits). Rotate to a 2048-bit key.

  #23
• ✓ No problematic flags #24

  No keys in test mode, revoked, or limited to SHA-1.

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

2 mail servers

Found

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: mx00.kundenserver.de, mx01.kundenserver.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.

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

Found

DANE (TLSA records)

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