[lug] Debian App DNS Issues

David L. Anselmi anselmi at anselmi.us
Wed Oct 29 18:51:33 MDT 2008


John Starkey wrote:
> Nate Duehr wrote:
>>
>> Is this a mobile machine, or does it stay on the same network?  DHCP 
>> or static?
> Static desktop on my SOHO network.
>>
>> Ultimately, whatever is in /etc/resolv.conf and /etc/nsswitch.conf are 
>> controlling what the DNS resolver on the system is going to give to 
>> applications running on it.
>>
> Any idea what actually hits those files and sends back to the app 
> though? I'm wondering if the vanilla apps are hitting a DNS library  or 
> binary other than the ones the Deb repo apps are. As I mentioned 
> Iceweasel (Deb's Firefox) works out of the box, but if I install a fresh 
> FF download from the site there's no DNS resolution.

I expect that it is all done by the libc resolver (which is modular so 
there are several libraries involved).  I'd also guess that the 
difference in behavior depends on what order the apps do their queries. 
  You could see that with something like strace, but for timeouts I'd 
use a network sniffer.  If a query is made that has to time out it would 
show up in the network traffic.

Dave




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