Engineer's DNS Intelligence Report
The following DNS record TTLs deviate from recommended values. Incorrect TTLs can cause caching issues, slow propagation, or unnecessary DNS traffic.
| Record Type | Observed TTL | Typical TTL | Severity | Context |
|---|---|---|---|---|
| NS | 6 hours (21600s) |
1 day (86400s) |
medium | NS TTL is below typical — observed 6 hours (21600s), typical value is 1 day (86400s). Short TTLs increase DNS query volume but enable faster propagation. If you are preparing for a migration or need rapid failover, this may be intentional (RFC 1035 §3.2.1). For steady-state production, consider 86400 seconds per NIST SP 800-53 SI-7 relevance guidance. Use the TTL Tuner for profile-specific recommendations. |
| SOA | 6 hours (21600s) |
1 hour (3600s) |
high | SOA TTL is above typical — observed 6 hours (21600s), typical value is 1 hour (3600s). Long TTLs reduce DNS query volume but slow propagation when records change. Consider 3600 seconds for a balance of performance and flexibility per NIST SP 800-53 SI-7 relevance guidance. |
Big Picture Questions
- How often do you actually change this record? If it hasn’t changed in months, a short TTL is generating unnecessary DNS queries without any benefit.
- Are you preparing for a migration or IP change? Short TTLs make sense temporarily — but should be raised back to 1 hour (3600s) once the change is complete.
- Every DNS lookup adds 20–150ms of latency. With a 60s TTL, returning visitors trigger a fresh lookup every minute. With 3600s, they get cached responses for an hour — faster page loads, no extra infrastructure needed.
- Google runs A records at ~30s because they operate a global anycast network and need to steer traffic dynamically. For a typical website without that infrastructure, copying those TTLs increases query volume with zero upside.
ns1.your-server.de
2026030126
hostmaster.valentin.run
| Timer | Value | RFC 1912 Range |
|---|---|---|
| Refresh | 86400s | 1,200–43,200s (20 min – 12 hrs) |
| Retry | 10800s | Fraction of Refresh |
| Expire | 3600000s | 1,209,600–2,419,200s (14–28 days) |
| Minimum (Neg. Cache) | 3600s | 300–86,400s (5 min – 1 day) |
DNSSEC is not enabled for this domain. DNSSEC provides cryptographic authentication of DNS responses, preventing cache poisoning and DNS spoofing attacks.
Your domain has DMARC reject — you qualify for BIMI, which displays your brand logo in receiving email clients that support it (Gmail, Apple Mail, Yahoo).
| Field | Value |
|---|---|
| Type | TXT |
| Host | default._bimi.valentin.run (BIMI default record) |
| Value | v=BIMI1; l=https://valentin.run/brand/logo.svg |
Email Security Methodology Can this domain be impersonated by email? No SPF and DMARC reject policy enforced
SPF Record RFC 7208 §4 Consistent
SPF valid with strict enforcement (-all), 0/10 lookups
DMARC is set to reject — enforcement is strong. However, some receivers may still reject messages on SPF hard fail before DKIM alignment is checked. Switching to ~all + p=reject would provide the same enforcement with full DMARC compatibility.
DMARC Policy RFC 7489 §6.3 Consistent
DMARC policy reject (100%) - excellent protection
pct= with t= (testing flag), add np= (non-existent subdomain policy), and mandate DNS tree walk for policy discovery instead of the Public Suffix List.DKIM Records RFC 6376 §3.6 Consistent
DKIM not discoverable via common selectors (large providers use rotating selectors)
l= tag body length vulnerability (attacker appends unsigned content to signed mail),
weak key exploitation (keys below 1024-bit are cryptographically breakable per RFC 6376 §3.3.3),
DKIM replay attacks (re-sending legitimately signed messages at scale)
MTA-STS RFC 8461 §3 Consistent
MTA-STS enforced - TLS required for 1 mail server(s)
- Mode:
enforce - Max Age: 7 days (604800 seconds)
- MX Patterns: mail.anva.ch
MTA-STS policy enforcement is evaluated in Mail Transport Security below.
TLS-RPT RFC 8460 §3 Consistent
TLS-RPT configured - receiving TLS delivery reports
DANE / TLSA Consistent Recon Methodology Can mail servers establish identity without a public CA? via MTA-STS (CA)
No DANE/TLSA records found (checked 1 MX host)
Two mechanisms protect email in transit. DANE is the primary standard; MTA-STS is the alternative for domains that cannot deploy DNSSEC:
- DNSSEC + DANE (RFC 7672) — Cryptographic chain of trust from DNS root to mail server certificate. Eliminates reliance on certificate authorities. No trust-on-first-use weakness. Requires DNSSEC.
- MTA-STS (RFC 8461) — HTTPS-based policy requiring TLS for mail delivery. Works without DNSSEC but relies on CA trust and is vulnerable on first use (§10). Created for domains where “deploying DNSSEC is undesirable or impractical” (§2).
Industry trend: Microsoft Exchange Online enforces inbound DANE with DNSSEC (GA October 2024), and providers like Proton Mail and Fastmail also support DANE. Google Workspace does not support DANE and relies on MTA-STS. Both mechanisms coexist because DANE is backward-compatible — senders skip the check if the domain isn't DNSSEC-signed (RFC 7672 §1.3).
Brand Security Can this brand be convincingly faked? Possible DMARC reject policy blocks email spoofing (RFC 7489 §6.3) and CAA restricts certificate issuance (RFC 8659 §4), but no BIMI brand verification — lookalike domains display identically in inboxes without visual proof of authenticity
BIMI BIMI Spec Consistent Warning
No valid BIMI record found