TTL

[MaD dUCK <madduck@madduck.net>]

alright, let's clear up this issue...

TTL is time to live, you knew that. time to live is a 32 bit integer
telling resolver caches how long (seconds) to keep an RR in memory.
negative TTL is telling them how long to store errors (no such
domain, minimum 3 hours).

TTL is really time to live, not the time until update. this means that
after TTL seconds, any resolver cache checks to see if the domain
still exists.

but for any request, any resolver cache only answers with the IP
address/in-addr ptr if, and only if, it has gotten this information
from the listed nameservers no longer than (Refresh) seconds ago. if i
have my refresh set to 5 minutes, and John does a lookup at 12:01,
Mary at 12:03, then only John's lookup will result in a forward to my
DNS server. if the Lisa does a lookup at 12:08, the request is
forwarded to the listed nameserver because the refresh time has
expired.

hope this makes sense. still digging for a document which will
explain this better than i can.

martin

ps: look at TTL, retry, refresh, expire, negative TTL, and then join
in into our chant to paul vixie: "make it intuitive in bind 10! make
it intuitive in bind 10"!

[greetings from the heart of the sun]# echo madduck@!#:1:s@\@@@.net
-- 
humpty was pushed.