[AusNOG] DNS forwarders (was Re: IPv6: Who's dual stacked? Why don't I look stacked?)

Peter Tiggerdine ptiggerdine at gmail.com
Fri Mar 8 14:27:10 EST 2013


Unless you're a teir two ISP or higher, pointing you're dns forwarders
to you're upstream providers assists with DNS load balancing like
Akamai and other content providers. Also take the weights of the root
name servers. Generally your lookup times will be quicker as well.

It's one of the many reasons why using opendns or google dns servers
isn't a great idea.

On Fri, Mar 8, 2013 at 12:13 PM, Paul Gear <ausnog at libertysys.com.au> wrote:
> On 03/08/2013 11:22 AM, Greg McLennan wrote:
>>
>> ...
>> Only thing to be mindfull is to make sure the DNS set in the mikrotik
>> points at a suitable public or ISP's DNS server that can also pass AAAA
>> records.
>
>
> I've never understood why anyone bothers with upstream DNS forwarders [1].
>
> Are there some strong technical (e.g. customer experiences breakage) or
> community-minded (e.g. the top-level servers can't handle it) reasons why we
> shouldn't just let all DNS queries go to the root? Most people seem to set
> their TTLs pretty low anyway [2], so it seems like a pointless exercise.
>
> Paul
>
> [1] Except for non-performance-related reasons, e.g. OpenDNS.
>
> [2] I'm too lazy to look up the reference, but i read a study of DNS TTLs
> which found that approximately (making up the numbers here) 95% of all TTLs
> were < 1 day.  Of those < 1 day, 95% were < 1 hour.  Of those < 1 hour, 95%
> were < 5 minutes.
>
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