Re: DNS TTL adherence

[Joe Maimon <jmaimon () ttec com>]

ennova2005-nanog () yahoo com wrote:

> Although you asked for DNS servers - it helps to remember that no matter 
> what the servers and resolvers do - IE will bring that behaviour to 
> naught in many cases
>
> http://support.microsoft.com/default.aspx?scid=KB;en-us;263558
>
>
> */"Thurman, Steven" <steven.thurman () wamu net>/* wrote:
>
>     Does anyone know if there is a research paper or statistics related
>     to what percentage of DNS servers do not adhere to advertised TTL
>     ’ s? I am looking for some verifiable research on this topic if it
>     is available.
>     Thanks,
>
>     Steve

And the dnscache resolver cache service in win2k and up.


http://support.microsoft.com/kb/318803/en-us
http://support.microsoft.com/kb/245437/EN-US/

If you are expecting hot cutovers to anything by utilizing DNS, sure 
seems that you need to expect to support traffic to the values of the 
old records for some time.

And if you are expecting very long TTL's to give you extra insurance for 
outages and what-nots, expect spotty effectiveness.