A question about using forwarders.

[Lee Fu-yuan]

Dear sir,

Thanks for your response. :)

But, according to my experiments, if the first forwarder server 
respond us NXDOMAIN message, my local dns stop querying
the second forwarder. 

In fact, I am not sure the actual meaning of "if IP1 fails to reply".
That is, if the IP1 responds NXDOMAIN, is that means IP1
fails to reply? or the "fails to reply" means "the DNS server 
running on IP1 is dead" ? 

Thanks.

With best regards,

Fu-Yuan Lee

On Thu, Dec 08, 2005 at 11:43:55AM +0530, raghavendra.sadaramachandra at wipro.com wrote:
> 
> Hi,
>  Plz use following configuration to get reply from any one out of 2 ip
> addresses configured. In named.conf file.
> 
> options {
>         directory "/var/named";
> 
>         forward only;
> 
>         forwarders {
> 		IP1;
> 		IP2;
>         };
> };
> 
> Here it first tries to contact IP1 and if IP1 fails to reply it contacts
> IP2.
> 
> 
> Plz look at the following also.
> 
> options {
>         directory "/var/named";
> 
>         // The "forward" option is only meaningful if you've defined
>         // forwarders.  "first" gives the normal BIND
>         // forwarding behavior, i.e. ask the forwarders first, and if
> that
>         // doesn't work then do the full lookup.  You can also say
>         // "forward only;" which is what used to be specified with
>         // "slave" or "options forward-only".  "only" will never attempt
>         // a full lookup; only the forwarders will be used.
>         forward first;
>         forwarders {
>                 1.2.3.4;
>                 5.6.7.8;
>         };
> 
> };
> 
> Regards,
> Raghavendra. S
> 
> -----Original Message-----
> From: bind-users-bounce at isc.org [mailto:bind-users-bounce at isc.org] On
> Behalf Of Lee Fu-yuan
> Sent: Thursday, December 08, 2005 11:28 AM
> To: bind-users at isc.org
> Cc: leefy at csie.nctu.edu.tw
> Subject: A question about using forwarders.
> 
> Hi everyone,
> 
> I have a question about the usage of the forwarder options.
> Consider a simple setting:
> 
> 	options {
> 		....
> 		....
> 		forwarders {IP_ADDRESS1; IP_ADDRESS2;};
> 		....
> 	};
> 
> Is it possbile that we can ask the DNS server to query the
> second forwarder with IP_ADDRESS2 if the first forwarder
> answers our query with NXDOMAIN message?
> 
> 
> Similarly, if none of the forwarders have the answer, i.e.,
> they all answers NXDOMAIN, can we let the DNS server perform
> interative query from root DNS servers?
> 
> Thanks a lot.
> 
> With best regards,
> 
> 
> --
> Lee, Fu-Yuan
> Distributed System and Network Security Lab.
> Dept. of Comp. Sci. & Info. Eng
> Nat'l Chiao Tung Univ.
> Hsinchu, Taiwan 30050, ROC
> E-Mail: leefy at csie.nctu.edu.tw
> 
> 
> 
> 
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-- 
Lee, Fu-Yuan
Distributed System and Network Security Lab.
Dept. of Comp. Sci. & Info. Eng
Nat'l Chiao Tung Univ.
Hsinchu, Taiwan 30050, ROC 
E-Mail: leefy at csie.nctu.edu.tw