DNS & Email Security Report for belastingdienst.nl

• A record presentcritical

  1 A record(s) found

• AAAA record presentrecommended

  1 AAAA record(s) found

• MX records presentrecommended

  2 MX record(s) found

• NS records presentcritical

  3 NS record(s) found

• SOA record presentcritical

  SOA record found

• Multiple nameserversrecommended

  3 nameservers configured ✓

• SOA serial formatinfo

  Serial 2006997018 (YYYYMMDDnn format)

• SOA timers validinfo

  Refresh: 14400s ✓, Retry: 1440s ✓, Expire: 604800s ✓

• No lame nameserversinfo

  3 NS all responding ✓

• Glue records presentinfo

  5 glue record(s)

• WWW record configuredinfo

  A record matches apex

• MX servers have PTR recordsinfo

  4 MX IPs all have PTR records ✓

• MX servers have FCrDNSinfo

  4 MX IPs have forward-confirmed reverse DNS ✓

• DNSSEC signedrecommended

  DNSSEC is enabled ✓

• DNSSEC validation OKcritical

  DNSSEC validates correctly ✓

• NSEC3 RFC 9276 compliantrecommended

  NSEC3 not RFC 9276 compliant: iterations=10 (must be 0), salt="1e2d76" (must be empty). Modern resolvers may reject this zone

• RRSIG signatures validrecommended

  RRSIG signature expires in 3 days — renewal needed

• Modern DNSSEC algorithmoptional

  RSA/SHA-256 (algorithm 8) — acceptable ✓

• DS digest algorithm modernrecommended

  DS digest: SHA-256 — modern ✓

• DNSKEY algorithm secureoptional

  DNSKEY: RSA/SHA-256 — acceptable, consider ECDSA (13) or Ed25519 (15)

• RRSIG TTL saferecommended

  Record TTLs do not exceed RRSIG validity periods ✓

• Chain of trust completecritical

  Complete chain: DNSKEY + DS + RRSIG ✓

• Website reachable via IPv6recommended

  1 AAAA record(s) ✓

• Mail servers reachable via IPv6recommended

  2/2 MX server(s) with IPv6 ✓

• Nameservers reachable via IPv6recommended

  2/3 NS server(s) with IPv6 ✓

• SPF record presentcritical

  v=spf1 redirect=_spf.belastingdienst.nl

• SPF syntax validcritical

  SPF syntax is correct ✓

• SPF policy strict (-all)recommended

  SPF uses ~all or ?all. Change to -all for strict enforcement

• DKIM foundrecommended

  No DKIM found. Configure DKIM signing with your email provider

• DMARC record presentrecommended

  v=DMARC1; p=reject; rua=mailto:[email protected]; sp=reject;

• DMARC policy quarantine or betterrecommended

  DMARC policy: reject ✓

• DMARC policy rejectoptional

  DMARC policy: reject ✓

• BIMI record presentoptional

  BIMI logo: https://vmc.digicert.eu/21f1c9f4-832a-4782-bb04-620805d23c17.svg

• BIMI configuration validoptional

  BIMI correctly configured ✓

• MTA-STS record presentoptional

  MTA-STS configured ✓

• MTA-STS policy enforcedoptional

  MTA-STS mode: testing. Set mode: enforce for full protection

• MX records validcritical

  2 MX record(s) ✓

• MX domains use DNSSECrecommended

  1/1 MX domain(s) use DNSSEC ✓

• MX DNSSEC validation OKrecommended

  MX DNSSEC validates correctly ✓

• Mail servers not blacklistedcritical

  1 MX server(s) checked against 16 blacklists - clean ✓

• No critical blacklist listingscritical

  No blacklist listings ✓

• CAA records presentrecommended

  5 CAA record(s) ✓

• CAA policy strictoptional

  CAA limits certificate authorities ✓

• TLSA records (DANE)optional

  2 DANE record(s) - configured according to best practices

• DANE configuration validoptional

  DANE records meet best practices ✓

• No sensitive info in TXTcritical

  No sensitive data leaked ✓

• Verification records reviewedinfo

  3 verification record(s): Microsoft 365, Google, Adobe IDP. Consider if all are still needed

• HTTPS availablecritical

  HTTPS working (status 200) ✓

• Valid certificatecritical

  Certificate chain is valid and trusted ✓

• HTTP redirects to HTTPScritical

  HTTP automatically redirects to HTTPS ✓

• HSTS enabledrecommended

  HSTS enabled (max-age=31536000) ✓

• HSTS max-age >= 1 yearoptional

  max-age=31536000 (≥1 year) ✓

• X-Frame-Options headerrecommended

  X-Frame-Options: SAMEORIGIN ✓

• X-Content-Type-Options headerrecommended

  X-Content-Type-Options: nosniff ✓

• Content-Security-Policy headerrecommended

  Content-Security-Policy configured ✓

• Referrer-Policy headerrecommended

  No Referrer-Policy header. Add Referrer-Policy: strict-origin-when-cross-origin

• security.txt presentoptional

  Contact: https://www.belastingdienst.nl/rfc2350

• security.txt validoptional

  security.txt has required Contact and Expires fields ✓

• HTTP/3 (QUIC) supportedoptional

  No HTTP/3 support detected No h3 in Alt-Svc header No HTTPS DNS record (type 65) QUIC probe inconclusive (Inconclusive - no QUIC reply (trigger may be dropped or UDP/443 filtered)) — not a negative signal

• QUIC UDP reachableinfo

  QUIC probe inconclusive (no reply — trigger may be dropped or UDP/443 filtered). Not a negative signal; h3 is judged from Alt-Svc / HTTPS record

• HTTPS DNS record (SVCB)optional

  No HTTPS DNS record (type 65). Add HTTPS record for faster HTTP/3 discovery: belastingdienst.nl IN HTTPS 1 . alpn="h3,h2"

Implement DKIM

Configure DKIM signing with your email provider and publish the DKIM public key in DNS.

Impact: Improves email deliverability and prevents spoofing

Enable HTTP/3 (QUIC)

Enable HTTP/3 for faster page loads and improved connection resilience. Nginx: add "listen 443 quic reuseport;" and "add_header Alt-Svc 'h3=":443"; ma=86400'". Caddy: HTTP/3 is enabled by default. Cloudflare: Enable under Speed → Protocol Optimization. Also add an HTTPS DNS record: example.com IN HTTPS 1 . alpn="h3,h2" Ensure UDP port 443 is open in your firewall (QUIC uses UDP, not TCP).

Impact: Faster page loads (0-RTT), better mobile performance, and connection migration between networks