DNS/サーバ調査/SOA/BINDについて、ここに記述してください。

古い情報だが

https://lists.isc.org/pipermail/bind-users/2001-April/026663.html

max-ncache-ttl

• To reduce network traffic and increase performance the server stores negative answers. max-ncache-ttl is used to set a maximum retention time for these answers in the server is seconds. The default max-ncache-ttl is 10800 seconds (3 hours). max-ncache-ttl cannot exceed the maximum retention time for ordinary (positive) answers (7 days) and will be silently truncated to 7 days if set to a value which is greater that 7 days.