On 28/03/2012, at 10:45 AM, Mauricio Freitas wrote:
I know of cases where people used to host DNS with a large ISP and after moving NS to other providers have to contact said ISP to �reset� DNS because their servers kept serving the old records for days� Even though people go on record saying �our servers respect TTLs� it seems some don�t�
I'd love to see some examples. I don't see why people would change TTLs - it's most likely to break things and increase support costs.
I still think this maybe a misunderstanding about how DNS works.
MMC
From: nznog-bounces@list.waikato.ac.nz [mailto:nznog-bounces@list.waikato.ac.nz] On Behalf Of Craig Whitmore
Sent: Wednesday, 28 March 2012 1:11 p.m.
To: Cameron Bradley; NZNOG Mailing-List
Subject: Re: [nznog] DNS TTL Mangling
> It has come to my attention in the course of moving the DNS for a number of domains that several of the ISPs in this country are mangling the TTLs on records queried by their recursive DNS servers. This behaviour seems to me to be undesirable in > situations where someone may have set a record to a shorter TTL to facilitate smoother movement between hosting providers. In the cases I�m seeing, records with TTLs of 14400 are being handed out with TTLs of 86400 by the service provider�s >servers.
If an ISP (or anyone) is breaking/changing TTL's (and maybe other stuff in DNS) on purpose I would think IMHO this is bad. Think would make DNSSEC signed zones fail + other stuff you have said as the ISP is playing around with it.
Maybe you don't want to name who you think is doing it but maybe if anyone is doing this they may want to comment on the reasoning behind it.
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