DNS & Email Security Report for tuta.com

• A record presentcritical

  1 A record(s) found

• AAAA record presentrecommended

  1 AAAA record(s) found

• MX records presentrecommended

  1 MX record(s) found

• NS records presentcritical

  4 NS record(s) found

• SOA record presentcritical

  SOA record found

• Multiple nameserversrecommended

  4 nameservers configured ✓

• SOA serial formatinfo

  Serial 1 (valid, managed DNS format)

• SOA timers validinfo

  Refresh: 7200s ✓, Retry: 900s ✓, Expire: 1209600s ✓

• No lame nameserversinfo

  4 NS all responding ✓

• Glue records presentinfo

  No glue needed

• WWW record configuredinfo

  A record matches apex

• MX servers have PTR recordsinfo

  3 MX IPs all have PTR records ✓

• MX servers have FCrDNSinfo

  3 MX IPs have forward-confirmed reverse DNS ✓

• DNSSEC signedrecommended

  DNSSEC is enabled ✓

• DNSSEC validation OKcritical

  DNSSEC validates correctly ✓

• NSEC3 RFC 9276 compliantrecommended

  Not applicable (domain uses NSEC or is not DNSSEC-signed)

• RRSIG signatures validrecommended

  RRSIG signature expires in 0 days — renewal needed

• Modern DNSSEC algorithmoptional

  ECDSA P-256 (algorithm 13) — modern ✓

• DS digest algorithm modernrecommended

  DS digest: SHA-256 — modern ✓

• DNSKEY algorithm secureoptional

  DNSKEY: ECDSA P-256 — modern ✓

• RRSIG TTL saferecommended

  A TTL (600s) exceeds RRSIG validity (0d). Cached records may outlive signatures

• Chain of trust completecritical

  Complete chain: DNSKEY + DS + RRSIG ✓

• Website reachable via IPv6recommended

  1 AAAA record(s) ✓

• Mail servers reachable via IPv6recommended

  0/1 MX servers have IPv6. Add AAAA records for your mail servers

• Nameservers reachable via IPv6recommended

  4/4 NS server(s) with IPv6 ✓

• SPF record presentcritical

  v=spf1 include:spf.tutanota.de -all

• SPF syntax validcritical

  SPF syntax is correct ✓

• SPF policy strict (-all)recommended

  SPF uses -all (hard fail) ✓

• DKIM foundrecommended

  DKIM selector: s1 ✓

• DMARC record presentrecommended

  v=DMARC1; p=quarantine; adkim=s

• DMARC policy quarantine or betterrecommended

  DMARC policy: quarantine ✓

• DMARC policy rejectoptional

  DMARC policy: quarantine. Set p=reject for maximum protection

• BIMI record presentoptional

  No BIMI record. Add TXT at default._bimi with logo URL (requires DMARC p=quarantine+)

• BIMI configuration validoptional

  No BIMI 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

  2 CAA record(s) ✓

• CAA policy strictoptional

  CAA limits certificate authorities ✓

• TLSA records (DANE)optional

  1 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

  1 verification record(s): Google. 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=63072000, includeSubDomains, preload) ✓

• HSTS max-age >= 1 yearoptional

  max-age=63072000 (≥1 year) ✓

• X-Frame-Options headerrecommended

  X-Frame-Options: DENY ✓

• X-Content-Type-Options headerrecommended

  X-Content-Type-Options: nosniff ✓

• Content-Security-Policy headerrecommended

  Content-Security-Policy configured ✓

• Referrer-Policy headerrecommended

  Referrer-Policy: no-referrer ✓

• 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: tuta.com IN HTTPS 1 . alpn="h3,h2"

IPv6 for mail servers

Add AAAA records for your MX servers to support email via IPv6.

Impact: Improves email reachability for IPv6 networks

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