[CentOS] /etc/resolv.conf - Number of Nameservers

John R Pierce pierce at hogranch.com
Mon Mar 10 05:02:50 UTC 2008


Manish Kathuria wrote:
> What is the maximum number of nameservers mentioned in /etc/resolv.conf
> which will be queried while looking up a hostname or IP address in the
> present version ? Earlier implementations had a ceiling of 3 name
> servers which could be queried. Has there been any increase ?
>   

only one server is ever queried.  only if it if it can't be reached at 
all will it fall back on the 2nd one (and if that can't be reached, the 
3rd)   a answer of 'host not found' from the primary server does /not/ 
trigger any fallback, instead it returns "not found".

so, why would you need more than 3 ?   DNS servers should have a .9999 
uptime.







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