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Re: question about bind9 from a clueless paranoid

On 20110406_121404, Brian wrote:
> On Tue 05 Apr 2011 at 23:24:47 -0600, Paul E Condon wrote:
> > On 20110404_190551, Brian wrote:
> > > I came to the conclusion there was no risk to the server (unbound in my
> > > case) as long as the server was not answering queries from outside my
> > > network. Reassurance would be welcome but I'm pretty sure of that.
> > > 
> > > Part of my testing was done at
> > > 
> > > https://www.grc.com/dns/dns.htm
> > 
> > Thanks for this! But there is a lot to read (and hopefully understand)
> > One specific question: what is mean by 'unbound' in this context?
> Unbound is a DNS server; an alternative to BIND.

OK, it's a pun ;-). Clueless I am.

> > > First with my ISP's servers in /etc/resolv.conf and then replacing them
> > > with and forwarding port 53 on the router to the machine
> > > running unbound.
> > And again here?
> Forwarding on the router isn't necessary to test the affect the router
> has on Source Port Randomness. Check /etc/bind/named.conf to ensure there
> is no forwarding of DNS requests to another resolver. Edit resolv.conf to
> use only 'nameserver'. Start BIND.
To do this usefully, I have to first figure out how to configure my newly
installed instance of BIND9. Correct? I don't think I'm there yet...

> http://entropy.dns-oarc.net/test/
This gave me a passing grade on the dns resolver run by my ISP. 
But there was one duplicate port number in the sample of 25 trys.
Maybe I should not worry, but I'm still curious about how the
system actually works.

Thanks for the pointer. Very fast.

> is quicker than grc.com to return a test result. You'll likely get a
> rating of POOR but, assuming queries from the internet are not served,
> your DNS cache cannot be poisoned because there is no access to it from
> the outside.

This contains information that's new to me. You seem to be saying
that my copy of BIND on my computer is building its own internal
cache. I don't see any reason why it couldn't contain a cache, but I
haven't read anywhere that it actually *does* have a cache
internally. Does it contain a cache?


Paul E Condon           

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