cwi.nl

SPF record published

Found

Record

v=spf1 ip4:192.16.191.0/27 ip4:192.174.88.179 ip4:192.174.88.180 ip4:13.58.74.171 include:_spf.surfmailfilter.nl include:projects5.greenlightsolutions.nl include:spf.protection.outlook.com ~all

DNS lookups

4 of 10

Void lookups

1 of 2

Problem

include:_spf.surfmailfilter.nl does not exist or has no records

Checks

• ✓ No deprecated ptr mechanism #1

  No ptr mechanism found in SPF record.
• !

  4 of 10 DNS lookups, with problems

  SPF record needs 4 DNS lookups (limit is 10). Problems found: include:_spf.surfmailfilter.nl 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.cwi.nl)

Found

Record

v=DMARC1;p=quarantine

Found at

_dmarc.cwi.nl

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.
• !

  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
• ✓ Subdomain policy: quarantine #20

  Subdomains are covered by policy 'quarantine'.

Selectors: default, selector1

Found

Selectors

default, selector1

_domainkey

NOERROR

Checks

• ✓ Keys found: default, selector1 #7

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

  1024-bit DKIM key

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

  #23
• ✓ No problematic flags #24

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

1 mail server

Found

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 4 MX addresss have a PTR record that resolves back to them.

no MTA-STS · no TLS-RPT · DANE on 1 of 1 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
• !

  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 1 MX host publish DNSSEC-validated TLSA records.