DNS & Email Security Report for postnl.nl

• A record presentcritical

  2 A record(s) found

• AAAA record presentrecommended

  2 AAAA record(s) found

• MX records presentrecommended

  1 MX record(s) found

• NS records presentcritical

  6 NS record(s) found

• SOA record presentcritical

  SOA record found

• Multiple nameserversrecommended

  6 nameservers configured ✓

• SOA serial formatinfo

  Serial 2018072339 (YYYYMMDDnn format)

• SOA timers validinfo

  Refresh: 28800s ✓, Retry: 3600s ✓, Expire: 2592000s ✗. Expire should be 604800-2419200s (1-4 weeks)

• No lame nameserversinfo

  6 NS all responding ✓

• Glue records presentinfo

  No glue needed

• WWW record configuredinfo

  CNAME: postnl.nl.edgekey.net

• MX servers have PTR recordsrecommended

  8 MX IPs all have PTR records ✓

• MX servers have FCrDNSrecommended

  8 MX IPs have forward-confirmed reverse DNS ✓

• DNSSEC signedrecommended

  DNSSEC is enabled ✓

• DNSSEC validation OKcritical

  DNSSEC validates correctly ✓

• NSEC3 RFC 9276 compliantrecommended

  NSEC3 iterations=0, salt=empty — RFC 9276 compliant ✓

• RRSIG signatures validrecommended

  RRSIG signature expires in 2 days — renewal needed

• Modern DNSSEC algorithmoptional

  RSA/SHA-512 (algorithm 10) — acceptable ✓

• DS digest algorithm modernrecommended

  DS digest: SHA-256 — modern ✓

• DNSKEY algorithm secureoptional

  DNSKEY: RSA/SHA-512 — 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

  2 AAAA record(s) ✓

• Mail servers reachable via IPv6recommended

  1/1 MX server(s) with IPv6 ✓

• Nameservers reachable via IPv6recommended

  6/6 NS server(s) with IPv6 ✓

• SPF record presentcritical

  v=spf1 ip4:87.233.130.51 ip4:83.149.98.72 include:spf.protection.outlook.com include:spf1.postnl.nl include:spf2.postnl.nl include:spf.topdesk.net -all

• SPF syntax validcritical

  SPF syntax is correct ✓

• SPF policy strict (-all)recommended

  SPF uses -all (hard fail) ✓

• DKIM foundrecommended

  DKIM selector: selector1 ✓

• DMARC record presentrecommended

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

• DMARC policy quarantine or betterrecommended

  DMARC policy: reject ✓

• DMARC policy rejectoptional

  DMARC policy: reject ✓

• BIMI record presentoptional

  BIMI logo: https://bimi.eu.dmarcmanager.app/eu-m9sha5zi/default/logo.svg

• BIMI configuration validoptional

  BIMI correctly configured ✓

• MTA-STS record presentoptional

  MTA-STS configured ✓

• MTA-STS policy enforcedoptional

  MTA-STS mode: enforce ✓

• MX records validcritical

  1 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

  No CAA records. Add CAA record to specify allowed certificate authorities

• CAA policy strictoptional

  CAA not strict. Add CAA 0 issue "letsencrypt.org" (or your CA) to restrict issuance

• TLSA records (DANE)optional

  No TLSA/DANE records. Add TLSA at _25._tcp.mail for DANE email encryption

• DANE configuration validoptional

  No DANE configured

• No sensitive info in TXTcritical

  No sensitive data leaked ✓

• Verification records reviewedinfo

  6 verification records found (Microsoft 365, Miro, OneTrust, Adobe IDP, Atlassian...). Review these - they reveal your tech stack to attackers. Remove unused service verifications

• HTTPS availablecritical

  HTTPS working (status 403) ✓

• Valid certificatecritical

  Certificate chain is valid and trusted ✓

• HTTP redirects to HTTPScritical

  HTTP does not redirect to HTTPS. Add redirect in web server config

• HSTS enabledrecommended

  HSTS enabled (max-age=31536000, includeSubDomains) ✓

• HSTS max-age >= 1 yearoptional

  max-age=31536000 (≥1 year) ✓

• X-Frame-Options headerrecommended

  No X-Frame-Options header. Add X-Frame-Options: DENY or SAMEORIGIN to prevent clickjacking

• X-Content-Type-Options headerrecommended

  No X-Content-Type-Options header. Add X-Content-Type-Options: nosniff to prevent MIME sniffing

• Content-Security-Policy headerrecommended

  No Content-Security-Policy header. Add CSP to prevent XSS and other injection attacks

• Referrer-Policy headerrecommended

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

• security.txt presentoptional

  No security.txt. Create /.well-known/security.txt with Contact and Expires fields (RFC 9116)

• security.txt validoptional

  No security.txt configured

• 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: postnl.nl IN HTTPS 1 . alpn="h3,h2"

Add CAA records

Define which Certificate Authorities may issue SSL certificates, for example: "0 issue letsencrypt.org"

Impact: Prevents unauthorized certificate issuance

Review verification TXT records

Your domain has many third-party verification records that reveal your tech stack (Google, Microsoft, Atlassian, etc.). Review each one: 1) Remove records for services no longer used 2) Consider if each service really needs domain verification 3) Use a subdomain for less critical services. This is an information disclosure issue - attackers can map your SaaS footprint.

Impact: Reduces reconnaissance surface and limits attacker knowledge of your infrastructure

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