SOA record fundementals

[Kevin Darcy]

Wouldn't it make more sense to have the names you care about resolve to both
addresses normally, and then just delete one of the addresses if a link fails?


- Kevin

Sam Pointer wrote:

> I have a quick question if anybody would be happy to oblige. Thanks in
> advance for any help/responses.
>
> As I understand it the Zone Data File for any given zone can only have one
> SOA record; fair enough. I also understand that the 1st field of the SOA
> record is the FQDN of the primary master nameserver for the given zone.;
> again fair enough.
>
> So, to build an example, lets assume my SOA record looks like this:
>
> mydomain.com.           IN      SOA     ns1.mydomain.com.
> root.mydomain.com. (..etc)
>
> Now, if I were to set up another *master* dns server for this zone, would
> the SOA record for *that* server look like:
>
> mydomain.com.           IN      SOA     ns2.mydomain.com. root.mydomain.com.
> (..etc)
>
>                                                 OR
>
> mydomain.com.           IN      SOA     ns1.mydomain.com. root.mydomain.com.
> (..etc)
>
> To put this in some context I'll explain what I am trying to accomplish. We
> have 2 leased lines from 2 different ISPs. All our boxes are multi-homed
> internally. I wish to have one set of DNS servers dishing out "ISP A"
> addresses and another set "ISP B" addresses. Why? I hear you ask. Well, the
> general premise is that (by keeping cachining TTL values very low - the
> boxes are all low-traffic) if we get a problem with in-bound connectivity
> with either of the ISPs we can take off-line their respective DNS servers at
> our end and stop advertising the addresses. This will force all DNS requests
> to resolve to the "good" ISP addresses thereby minimising distruption. When
> everything clears itself up we can bring the DNS servers back up and have
> both lines active again for in-bound traffic.
>
> In short I want 2 different DNS servers on 2 different IP ranges to serve
> the same domain names.
>
> Again, thanks.
>