dnsmasq for caching

[John Summerfield]

kwhiskerz wrote:
> This is what I have done:
> 
> I have made a file, resolv.servers with the nameservers I want to use. I have 
> edited resolv.conf so that it looks at 127.0.0.1. I have put PEERDNS=no into 
> ifcfg-eth0 so that resolv.conf does not get overwritten at boot. I have 
> edited dnsmasq.conf to use only resolv.servers in strict order.
> 
> I am able to connect to the internet and I can verify that I am using my 
> chosen nameservers, so this setup appears to be working.
> 
> I have set up 2 computers and have exactly the same files in both.
> 
> On one computer, when I type dig someplace.com the search takes ~300ms and 
> subsequently ~0ms and no lights flash on my adsl router. Caching appears to 
> work.
> 
> On the other computer, when I type dig someplace.com the search takes ~300ms 
> and subsequently ~35ms and lights flash on my adsl router. I suspect caching 
> is not working.
> 
> What is happening here? How does one properly set up dnsmasq to do dns 
> caching? Why is the same setup acting differently on the 2 machines? Network 
> Manager is not enabled on either machine.
> 
> Any ideas?
> 
Seems to me caching _is_ working, though why the difference I cannot say.

Use tcpdump* to listen to the relevant interface, port 53 on each and 
see what's the difference.

* Or wireshark. Wireshark has a nice GUI.

-- 

Cheers
John

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