How to setup a backup NameServer?

[houguanghua]

Steve,
 
Thanks a lot for your advice.
 
Guanghua 
 
> Date: Sun, 4 May 2014 09:26:00 +0100
> Subject: Re: How to setup a backup NameServer?
> From: sjcarr at gmail.com
> To: houguanghua at hotmail.com
> CC: bind-users at lists.isc.org
> 
> On 4 May 2014 02:15, houguanghua <houguanghua at hotmail.com> wrote:
> > These zones are not owned by ISP, such as: yahoo.com, facebook.com...
> > If such backup dns server is ready, ISP will talk to these WEB sites to keep
> > synchronization with their authority NSs.
> > It's maybe a huge project.
> 
> It's an impossible project. Exactly how are you going to handle DNS
> records that only have a 30 second TTL? Sites have TTLs that low to
> allow /them/ to cope with DR/failover scenarios. If you are keeping
> old DNS records past that TTL then when the site itself has changed to
> a different IP you are still going to be handing out the old IP
> address to your users. And equally the site may have a custom DNS
> implementation which gives you different IP addresses through
> round-robin/load balancing, how will you handle this? You will have no
> knowledge of their DNS infrastructure to determine how/what they are
> doing to return the correct records.
> 
> Please go and read on how DNS actually works and use it properly
> instead of trying to invent a method which just wont work. You have no
> control over the Internet, so don't try to control it.
> 
> Steve
 		 	   		  
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