Stop using low DNS TTLs
7 days ago
- #Caching
- #Latency
- #DNS
- DNS latency is crucial for a good online experience, and minimizing it involves careful selection of DNS servers and anonymization relays.
- DNS was designed to be cacheable, with records having a Time-to-Live (TTL) set by zone administrators to avoid unnecessary traffic.
- A study reveals that most DNS records have very low TTLs, with half of the Internet having a TTL of 1 minute or less, making DNS caching inefficient.
- Low TTLs are often due to legacy settings, misconceptions about DNS-based load balancing, and administrators wanting immediate changes.
- CDNs and load balancers exacerbate the issue by combining CNAME records with short TTLs, leading to frequent DNS queries.
- Simulations show that setting a minimum TTL of 40 minutes could significantly reduce the number of unnecessary DNS queries, improving latency and privacy.
- The article suggests revisiting TTL settings on authoritative DNS servers and using local DNS caches with minimum TTL settings to mitigate inefficiencies.