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The default CloudFlare TTL for NX (non-existing) records is about three hours, which is a bit of a bummer if I accidentally query a DNS name I haven't created yet. The CloudFlare API calls to create and edit records make no mention of the NX record. Is there some way to set this?

l0b0
  • 7,453

2 Answers2

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It is controlled by the "negative TTL" field (last field) in the SOA record for the zone in question. Can't help you more since you didn't provide any domain name(s).

Edit --

But as an example, if the domain name is something-of-yours.cloudflare.com, here's where the non-existent cache value comes from (below). It's the last value returned in the SOA record, that is the negative-caching TTL field, and it's 3600 (seconds) = 1 hour in this case.

Whoever is the admin for the zone cloudflare.com (first field ot the SOA) controls this value, and the e-mail address is apparently dns@cloudflare.com.

Notice there is no "NX" record returned, there's no such thing.

$ dig something-of-yours.cloudflare.com

; <<>> DiG 9.10.0rc2-1+b1-Debian <<>> something-of-yours.cloudflare.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 51707
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;something-of-yours.cloudflare.com. IN  A

;; AUTHORITY SECTION:
cloudflare.com.         3600    IN      SOA     ns3.cloudflare.com. dns.cloudflare.com. 2020742566 10000 2400 604800 3600

;; Query time: 121 msec
milli
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1

The answer unfortunately is that Cloudflare does not allow the NX TTL to be changed. Today, the value is 1 hour.

$ dig soa my-domain-on-cloudflare.com

; <<>> DiG 9.10.6 <<>> soa my-domain-on-cloudflare.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 59079
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;my-domain-on-cloudflare.com.           IN  SOA

;; ANSWER SECTION:
my-domain-on-cloudflare.com.        3600    IN  SOA daisy.ns.cloudflare.com. dns.cloudflare.com. 2030614699 10000 2400 604800 3600

;; Query time: 38 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Fri Apr 05 12:16:45 EDT 2019
;; MSG SIZE  rcvd: 102
Robin Daugherty
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