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cwi.nl

Checked 2026-10-21 21:00 UTC · first added 2026-10-21
!Check could not complete

Domain & DNS

error

27 passed 1 warn 0 failed 1 errors

lookups failed for rdap; results are incomplete

Areas

iRegistration iDelegation iNameservers ✓SOA !DNSSEC iRecords

Problems

  • !
    NSEC3 with extra iterations or salt
    DNSSEC · NSEC3 uses 0 iterations and a 8-byte salt. RFC 9276 recommends 0 iterations and no salt: extra iterations cost resolvers CPU and add no real protection, and some validators treat high counts as insecure.
    #31

Recent checks

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Domain & DNS report for cwi.nl ›

Mail

warn

23 passed 8 warn 0 failed

Areas

!SPF !DMARC !DKIM ✓DNSSEC !MX !TLS iBIMI

Problems

  • !
    4 of 10 DNS lookups, with problems
    SPF · SPF record needs 4 DNS lookups (limit is 10). Problems found: include:_spf.surfmailfilter.nl does not exist or has no records.
    #2
  • !
    Policy: quarantine
    DMARC · DMARC policy is set to 'quarantine'. Consider upgrading to 'reject' for stronger protection once you've verified legitimate emails are passing authentication.
    #4
  • !
    Single MX host, no backup
    MX · Only one MX record found. For better email reliability, consider adding at least one backup MX server.
    #12
  • !
    No aggregate reports (rua)
    DMARC · DMARC record has no rua tag, so you receive no aggregate reports about who sends mail as your domain. Add rua=mailto:...
    #19
  • !
    1024-bit DKIM key
    DKIM · 1024-bit RSA keys are the minimum and are considered weak today: default (1024 bits). Rotate to a 2048-bit key.
    #23
  • !
    1 void lookup
    SPF · 1 include/redirect target does not exist or has no records (limit is 2). This usually is a stale include; remove it.
    #26
  • !
    Not configured
    TLS · 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
    TLS · 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

Recent checks

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Mail report for cwi.nl ›