Some domains don't resolve.

Sten Carlsen ccc2716 at vip.cybercity.dk
Sat Jun 7 23:33:59 UTC 2008


I am sorry if this came out that way. I actually tried to agree with you
but based on my own experience.

I believe the original question assumed that forwarding was beneficial,
I will just say that my experience is different.

Barry Margolin wrote:
> In article <g2dhd2$1mb8$1 at sf1.isc.org>,
>  Sten Carlsen <ccc2716 at vip.cybercity.dk> wrote:
>
>   
>> The question as I read it, is if a very small amount of users will 
>> benefit most from using the cached lookups of a large number of users 
>> (the whole ISP population) or from having their own independent resolver.
>>
>> I have that situation here, I first used forward but later switched to 
>> just resolving. My feeling (I have no statistics) is clearly in favour 
>> of NOT forwarding. I don't see any speed penalty in real life but got 
>> rid of some mysterious issues that happened while forwarding and the 
>> speed seems to be higher.
>>     
>
> I'm not saying that I recommend forwarding.  I don't, because it adds an 
> extra layer of dependency, and the benefit is probably not worth it.
>
> I was just refuting the guy who said that the theory that you get better 
> cache hits is a myth.
>
>   
>> Barry Margolin wrote:
>>     
>>> In article <g2aeee$1bb9$1 at sf1.isc.org>, Kevin Darcy <kcd at chrysler.com> 
>>> wrote:
>>>
>>>   
>>>       
>>>> Barry Margolin wrote:
>>>>     
>>>>         
>>>>> But if your ISP has 100,000 users of the same caching server, it will be 
>>>>> cached if any of 1,000 users have accessed it recently.  For any one of 
>>>>> them, there's only a 0.1% chance that their lookup will be the one that 
>>>>> has to wait for fetching from the source.
>>>>>   
>>>>>       
>>>>>           
>>>> And if you have 100,000 users using the same caching server, it's likely 
>>>> to experience big spikes of activity (e.g. several thousands of queries, 
>>>> within the course of less than a second), during which time some users 
>>>> will experience some extra delay in getting their queries resolved.
>>>>     
>>>>         
>>> Certainly if the nameserver is not engineered to handle the load it's a 
>>> bad idea to use it as a forwarder.  That's a completely different issue 
>>> than whether it's useful to share caches via a forwarding hierarchy.
>>>
>>>
>>>       
>
>   

-- 
Best regards

Sten Carlsen

No improvements come from shouting:

        "MALE BOVINE MANURE!!!"


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