To:
Robert Elz <kre@munnari.OZ.AU>
cc:
Daniel Senie <dts@senie.com>, ngtrans@sunroof.eng.sun.com, namedroppers@ops.ietf.org, ipng@sunroof.eng.sun.com, dnsop@cafax.se
From:
Keith Moore <moore@cs.utk.edu>
Date:
Wed, 08 Aug 2001 12:56:41 -0400
In-reply-to:
Your message of "Wed, 08 Aug 2001 23:35:12 +0700." <5162.997288512@brandenburg.cs.mu.OZ.AU>
Sender:
owner-dnsop@cafax.se
Subject:
Re: (ngtrans) Joint DNSEXT & NGTRANS summary
> | So, the question is, to > | use this effectively, do zones have to be set up with their TTL set to 60 > | seconds? > > No, bit when you set a TTL on a record in the DNS, that's a promise that > the data isn't going to change from the time someone fetches the record > until the TTL has expired. actually, it's not. if that were the case, we could never change a name-to-address binding without first setting TTL to zero (or providing a mechanism that allows them to diminish to zero) and waiting for older TTLs to expire. it's somewhat more realistic to say that a TTL indicates (for an address record) that any services referred to by the DNS name will continue to be available at that IP address until the TTL expires, if they're available at all. it's even more realistic to say that TTL indicates the amount of time for which the DNS administrator is willing to accept that the services associated with the DNS name will be effectively unavailable, should he/she need to change the addresses. Keith