I think I ought to qualify my earlier email - I certainly didn't mean to suggest that this would happen. I meant to merely comment on what the expected increase in load might be if we did see a trend towards lower TTLs. Any trend towards lower TTLs would be outside of Verisign's control anyhow, and if it did happen, it would no doubt be a gradual effect. Which brings me back to my original question - does anyone know of any stastics for TTL values? Sam On Thu, 22 Jul 2004, Henry Linneweh wrote:
Before a big panic starts, they can restore it back to the way it was if there is an event of such proportion to totally hoze the entire network or any major portion of it, until they fix any major issue with these changes....
-Henry
--- Sam Stickland <sam_ml@spacething.org> wrote:
Well, a naive calculation, based on reducing the TTL to 15 mins from 24 hours to match Verisign's new update times, would suggest that the number of queries would increase by (24 * 60) / 15 = 96 times? (or twice that if you factor in for the Nyquist interval).
Any there any resources out there there that have information on global DNS statistics? ie. the average TTL currently in use.
But I guess it remains to be seen if this will have a knock on effect like that described below. Verisign are only doing this for the nameserver records at present time - it just depends on whether expection for such rapid changes gets pushed on down.
Sam
On Thu, 22 Jul 2004, Ray Plzak wrote:
Good point! You can reduce TTLs to such a point
become preoccupied with doing something other than
that the servers will providing answers.
Ray
-----Original Message----- From: owner-nanog@merit.edu
[mailto:owner-nanog@merit.edu] On Behalf Of
Daniel Karrenberg Sent: Thursday, July 22, 2004 3:12 AM To: Matt Larson Cc: nanog@merit.edu Subject: Re: VeriSign's rapid DNS updates in .com/.net
Matt, others,
I am a quite concerned about these zone update speed improvements because they are likely to result in considerable pressure to reduce TTLs **throughout the DNS** for little to no good reason.
It will not be long before the marketeers will discover that they do not deliver what they (implicitly) promise to customers in case of **changes and removals** rather than just additions to a zone.
Reducing TTLs across the board will be the obvious *soloution*.
Yet, the DNS architecture is built around effective caching!
Are we sure that the DNS as a whole will remain operational when (not if) this happens in a significant way?
Can we still mitigate that trend by education of marketeers and users?
Daniel