[dns-operations] Quick analysis of TLD SOA's

Joe Abley jabley at hopcount.ca
Wed Jul 13 16:47:07 UTC 2011

On 2011-07-13, at 11:30, Jake Zack wrote:

> And NegTTL expire times...more than half are set to 3 hours or less.

Remember that it's the minimum value of the SOA TTL and the (RFC1035-termed) MINIMUM field that is supposed to determine the negative cache TTL. So if MINIMUM = 3h but SOA TTL = 3s then the negative cache TTL will be 3s, not 3h. People forget this.

For a TLD registry it seems to me that the negative cache TTL might well be a function of how frequently new zones are published, no doubt modulated by other factors.


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