Setting up a backup DNS also used by local users

[Kevin Darcy]

If both nameservers are in the NS records for your zone, then
*both* nameservers will get sent queries for your zone, and therefore you have
no control over whether a client goes to your "primary" webserver or your
"backup" webserver. You can't implement "primary/fallback" reliably in this way
(unless you happen to control *all* of the nameservers which could possibly be
caching answers for queries in your domain, which I assume you don't).

Mirror your website to both locations and then it won't matter which website a
client goes to.

Or, a more expensive solution is to buy a commercial product which will
frontend both webservers behind a single IP address.


- Kevin

Chris wrote:

> Here is my problem :
>
> Place Number 1: C Class Network - Primary DNS server - Web Server - No local
> user on this network
> Place Number 2: Another C Class Network - Secondary DNS - Backup Web
> Server - Local users on this network - sub domains exists.
>
> If a problem occurs with the first network the primary DNS will no more be
> available, www.mydomain.com will not be resolved (and the main web server is
> no more available).
> I suppose that the request to resolve www.mydomain.com will be sent to the
> secondary DNS, be resolved to another IP and the user will surf on the
> backup web server.
> I suppose things will goes that way.
>
> But there is a problem : the users on the local network of "Place number 2"
> will always surf the backup web server never the main !! But they HAVE TO !
> When they uses mydomain.com they goes right to the backup web...
>
> In fact I would like the secondary DNS not to responde to a local request on
> mydomain.com. It should resolve mydomain.com only when the request comes
> from the outside.
>
> The only solution I see is to create CNAMEs on the primary DNS like
> www2.mydomain.com, mail2.mydomain.com, ftp2.mydomain.com that will not
> exists on the secondary DNS... This way I can surf mydomain.com if I use
> www2 and the backup if I use www...
>
> But it's seems an ugly way ! Any idea ?