Consistent TTL
TTL (Time To Live) tells DNS servers how long they should remember your site's address before re-checking it. Like an expiry label: after th…
Analyse my site for freeUnderstanding "Consistent TTL"
A DNS record's TTL (Time To Live) tells resolvers how long they may cache the response before re-checking it with the authoritative server. A short TTL speeds up the propagation of any future DNS change (useful ahead of a planned migration), at the cost of a higher volume of DNS queries and a slightly increased resolution latency for visitors. A permanently very short TTL is usually a sign of a configuration never readjusted after a one-off event.
This is an operational performance and best-practice check rather than a direct security one — a poorly tuned TTL creates no vulnerability, but degrades the overall efficiency of the DNS system.
How TheSiteFuse checks "Consistent TTL"
TheSiteFuse resolves the root domain's A record and reads the TTL value returned in the DNS response (rrset.ttl). A TTL below 300 seconds (5 minutes) triggers a warning — too short for permanent use, barring a temporary justified reason (an ongoing migration). Above that threshold, the check passes.
Why "Consistent TTL" matters
- Unnecessarily high DNS query volume — a very short TTL forces every resolver worldwide to re-check your DNS record far more often than necessary, increasing load on your DNS servers with no benefit for a stable domain.
- Slightly increased latency for visitors — a more frequently expiring DNS cache means more visitors experience the full DNS resolution time rather than an instant answer from their ISP's local cache.
- Sign of an operational oversight — a TTL temporarily lowered before a DNS migration and never raised back afterward is the most common explanation for an abnormally short TTL detected long after the fact.
Fix "Consistent TTL" step by step
Recommended values by context
- Normal use, stable domain: 3600s (1 hour) to 86400s (24 hours) — a good balance between performance and flexibility.
- Before a planned migration: temporarily lower to 300s (5 minutes) a few days before the change, to speed up propagation on the day.
- After the migration: raise the TTL back to its normal value once the change is stabilised and validated (typically 24 to 48h after).
Modification
TTL is configured directly in your registrar's or host's DNS management interface, at the level of each individual record.
Verification
dig yourdomain.com A # Check the TTL column in the ANSWER section
Reference resource
To deepen your understanding of the technical concepts behind this check, see the dedicated Wikipedia article.
Wikipedia — Consistent TTLDoes your site pass this check?
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