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

John R Pierce pierce at hogranch.com
Mon Mar 10 08:55:37 UTC 2008


Manish Kathuria wrote:
>
> The idea is to switch between multiple internet links for the same
> internal network, without making frequent changes to /etc/resolv.conf.
> The ISPs here don't allow DNS look ups from an IP not belong to their
> address, so a number of look up requests get denied when the outgoing
> connection is through another ISP. Of course, I can run a caching
> nameserver on the small network or use Open DNS servers but that adds to
> the delay.
>   

not half as bad as having every lookup try and go to the first server in 
/etc/resolv.conf, then fail, and try the 2nd, repeating until one resolves.

sounds like you should be running a caching name server, maybe even 
something thats aware of your ISP multiplexing scheme so it can 
dynmically choose forwarders


a local caching name server shouldn't add any significant delay, and 
will greatly speed up frequent lookups.



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