Why did this occur when turning off recursion

[Brad Knowles]

At 7:28 AM -0500 5/22/01, King, John (Greg) (OAO-HOU) wrote:

>  I added the following named.conf entries
>
>  recursion no;
>  fetch-glue no;
>
>  Restarted BIND and my entire home network could not resolve anything. I
>  thought the server would respond back with the root server list telling my
>  system where it needed to go to find its information (and not use my dns
>  server to do the lookup). Instead nothing resolved at all. Took the entries
>  out and everything worked again.

	The resolver that is built into most OSes cannot handle 
recursion.  Instead, it depends on a nameserver to that for it.  What 
you had is a resolver pointed at the nameserver on the local machine, 
and everything worked fine.  When you turned off recursion on the 
local nameserver, the resolver broke because it can't handle 
recursion on its own.


	The lesson you should take away from this is that you will almost 
always need a local caching/recursive nameserver for local machines 
to use, in order to be able to resolve any hostnames for the rest of 
the 'net.

	You *MAY* also need an authoritative nameserver, so that people 
from the outside world can find out about your machines.  If you do, 
then I would encourage you to set that up on a totally separate 
machine and make sure that you turn off recursion on it.  It's not 
strictly necessary to set it up on a separate machine, but it does 
make configuring and managing the machines much easier.

-- 
Brad Knowles, <brad.knowles at skynet.be>

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