On 26/07/2019 14:45, Leroy Tennison wrote: > This brings up one of the caveats for (at least ISC) DNS, if the master goes down the slaves will take over for a time but eventually will stop serving for the domains of the master if it remains down too long. If my (sometimes faulty) memory serves me well it is in the three day range (but configurable) which is ample time unless the problem occurs early in a holiday weekend and and the notification/escalation process isn't what it should be (Murphey's Law)... The value you refer to is the SOA record _expire_ value for a zone, I believe is should be set to between 14 and 28 days. https://en.wikipedia.org/wiki/SOA_record