Steven,
 
Your solution is very good. It can forward the queries to the specified name 
servers first.
 
But if the specified name server is enabled only when normal dns query process 
is down. How to configure the local DNS server?  The detailed scenario is 
descibed in below figure:
 

                                            --------------
                                           |    Root         |                  
                
                                           | nameServer |
                                         /  -------------
                                     ②/           
                                       /
     ----------                   ------------                       
-------------
    | Client     | __①____\ |   Local         | ___③_____\ |  Authority    |    
  
    | Resolver |             / | DNS Server |       X       / | DNS Server  |
     ----------                   ------------                        
-------------
                                       \                     
                                        \④
                                         \
                                          \  ------------
                                            |  Hidden      |
                                            | DNS Server |
                                             ------------
Normally,
  1) A internet user wants to access www.abc.com, a DNS request is sent to 
local DNS server
  2) Local DNS server queries the root name server, the .com name server to get 
the Authority Name Server of abc.com  
 3) local DNS server queries the Authority name server, and gets the IP
 
But when the Authority name server is down, the internet user won't get  the IP 
address.  My solution is as follows:
     a) A hidden name server with low performance is deployed. When authority 
name server can't be accessed, local dns server will access the hidden server.
     b)The hidden server is never used in normal situation. It act as a cold 
backup for authority name server.
     c) The zone file in the hidden server is the same as that configuration in 
the authority name server 
     d) The hidden name server doesn't appear in the NS records of  authority 
name server 
 
Btw, all above doesn't consider the cache in the local dns server.
 
 
 Best Regards,
Guanghua

 
> Date: Mon, 17 Feb 2014 09:09:13 +0000
> Subject: Re: how to modify the cache
> From: sjc...@gmail.com
> To: houguang...@hotmail.com
> CC: bind-users@lists.isc.org
> 
> On 17 February 2014 01:17, houguanghua <houguang...@hotmail.com> wrote:
> > I want to override the IP address of NS, for I want to use other authority
> > DNS which isn't registered.
> 
> For that you use forwarding. Create a zone statement for the zone in
> question and forward the queries to a different name server. You don't
> need to mess with the cache.
> 
> https://mknowles.com.au/wordpress/2009/07/20/bind-forwarding-zone/
                                          
_______________________________________________
Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe 
from this list

bind-users mailing list
bind-users@lists.isc.org
https://lists.isc.org/mailman/listinfo/bind-users

Reply via email to