Comment by hannasm

  > patched an Encrypted DNS Server to store the original TTL of a response, defined as the minimum TTL of its records, for each incoming query

The article seems to be based on capturing live dns data from some real network. While it may be true that persistent connections help reduce ttl it certainly seems like the article is accounting for that unless their network is only using http1.0 for some reason.

I agree that low TTL could help during an outage if you actually wanted to move your workload somewhere else, and I didn't see it mentioned in the article, but I've never actually seen this done in my experience, setting TTL extremely low for some sort of extreme DR scenario smells like an anti pattern to me.

Consider the counterpoint, having high TTL can prevent your service going down if the dns server crashes or loses connectivity.