Is the `default TTL` from SOA record configurable in Cloudflare?

dns

#1

Hi community,
Could I please get a hand in understanding why if we lookup a DNS record that doesn’t exist, we must wait 1800 seconds before our name server will try to resolve it again?

Here’s what we’re testing:

So my questions:
Is the default TTL in the Start of Authority (SOA) record what determines when other name servers will attempt to look for this doesnotexist.example.com name in the future?
Is the default TTL configurable in Cloudflare?
Howcome this article seems to suggest that the default TTL is 300 seconds (or is that the Automatic TTL and only applies to DNS records that have already existed previously?)

Because here’s my testing:

C:\Users\somerandomuser>nslookup
Default Server:  google-public-dns-a.google.com
Address:  8.8.8.8

> set type=soa
> example.com
Server:  google-public-dns-a.google.com
Address:  8.8.8.8

Non-authoritative answer:
example.com
        primary name server = adi.ns.cloudflare.com
        responsible mail addr = dns.cloudflare.com
        serial  = xxxx354900
        refresh = 10000 (2 hours 46 mins 40 secs)
        retry   = 2400 (40 mins)
        expire  = 604800 (7 days)
        default TTL = 3600 (1 hour)
> example.com
Server:  google-public-dns-a.google.com
Address:  8.8.8.8

I see the default TTL is set to 3600 seconds but when I check out the dns.google.com resolver, I see that it’s TTL is always set to 1800 seconds. I try this with a record where i’m the first person to check and it always seems to start the count-down from 1800 seconds.

So is google just halving the TTL arbitrarily, or is there some RFC that says this is what name servers should do?

I would love anyone’s help here! thanks :slight_smile:


#2

I contacted cloudflare support and the answer is:

There is currently no way to set what is called the “Negative TTL” component of the SOA record which is set to 1 hour by default


#3

This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.