DNS TTL adherence

Joe Maimon jmaimon at ttec.com
Wed Mar 15 02:32:40 UTC 2006



ennova2005-nanog at 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 at 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.





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