[hobbit] /etc/resolv.conf and DNS error (http test)

Dominique Frise Dominique.Frise at unil.ch
Fri Oct 5 20:53:55 CEST 2007


Hi Dave,

Sorry for the delay, I've been pretty busy those days....
I know that the ARES resolver can be by-passed. I just wanted to point out a 
possible bug in the Hobit code.

Thanks.

Dominique
UNIL - University of Lausanne
Haertig, David F (Dave) wrote:
> Did you try modifying ...../server/etc/hobbitlaunch.cfg?
> 
> Change the line:
> 
> CMD bbtest-net --report --ping --checkresponse
> 
> to:
> 
> CMD bbtest-net --report --ping --checkresponse --no-ares
> 
> I don't know if you need to restart Hobbit server after this for it to
> take effect.  Wouldn't hurt.
> 
> -----Original Message-----
> From: Dominique Frise [mailto:Dominique.Frise at unil.ch] 
> Sent: Wednesday, September 26, 2007 9:44 AM
> To: hobbit at hswn.dk
> Subject: Re: [hobbit] /etc/resolv.conf and DNS error (http test)
> 
> 
> 
> Haertig, David F (Dave) wrote:
>> Try adding a "search" line to resolv.conf.  e.g., "search
> example.com".
>> Your existing domain line should set this as your default search, but 
>> maybe it's not?  Try explicitly setting it by adding a search line.  
>> But you imply your problem is intermitant, so it's probably not 
>> default search that's getting you.  Do you get the same intermittant 
>> failures when you run "nslookup www.example.com" repeatedly from the 
>> command line?  I believe when you have multiple nameservers listed 
>> they are all queried, and the first to respond wins.  I don't think 
>> Solaris waits for the first to fail before moving on to the second 
>> like you say.  I'm not 100% sure about this though.
>>
>> Note: I believe Solaris only uses the first six entries that are 
>> listed on a resolv.conf "search" line, ignoring the rest.  Something 
>> to keep in mind if you use this.
>>
>> -----Original Message-----
>> From: Dominique Frise [mailto:Dominique.Frise at unil.ch]
>> Sent: Wednesday, September 26, 2007 12:43 AM
>> To: hobbit at hswn.dk
>> Subject: [hobbit] /etc/resolv.conf and DNS error (http test)
>>
>> Hi,
>>
>> We have tried following settings in the Hobbit server's 
>> /etc/resolv.conf (Solaris 9)
>>
>> domain example.com
>> nameserver 1.2.3.4
>> nameserver 1.2.3.5
>> options timeout:1
>> options retry:1
>>
>>
>> While the first and second nameserver are up and running we receive 
>> sometimes "DNS error" on http checks like http://www.example.com.
>>
>> Assuming that the first nameserver is not responding within the 
>> timeout, the second should be queried by the Hobbit resolver and get 
>> the response.
>>
>> Is there something that we are missing?
>>
>>
>> Dominique
>> UNIL - University of Lausanne
>>
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>>
>>
> 
> There are no intermittent problem while using nslookup or any other tool
> relying on the default resolver under Solaris.
> I think the problem comes from the ARES resolver that Hobbit uses
> internally. 
> Maybe the timeouts and retry setting are not interpreted the same way as
> the default resolver does.
> I have no time to look at the code but perhaps Henrik has an answer...
> 
> Thanks.
> 
> Dominique
> 
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> 
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> 



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