about "query time" (caching)

[Pol Hallen]

> In the third case, the A records had expired from the cache (since the TTL on those records is 300 seconds = 5 minutes), so your resolver needed to fetch a fresh set from the yahoo.it nameservers -- the NS records of which were most likely cached from the first lookup -- but it didn't need to follow the referral chain all of the way down from the root. 19 msec.

thanks Kevin, now it's clear

is there a way to keep update cache of queries users will do?

Pol