1 DNS entry -> 2 IPs

[Kevin Darcy]

Alexis Albinet wrote:

> Hi,
>
> How to make a priority acces if I had 2 systems for 1 entry  www?
>
> Exemple:
> I had two entries in a domain :
>
> www        IN    A    x.x.x.15
> www        IN    A    x.x.x.16
>
> I would like that the x.x.x.15 system always answer when I 'ping' www.
> How to make this ?

Check out the rrset-order statement, which is available in BIND 8.2.x.
Unfortunately, this is not a perfect solution: not only does it require
that you define it on all of the authoritative servers (not always
feasible, since often your slaves are run by service providers), but
there could also be some servers which cache the data and then give it
back out in the default "round-robin" order. You can defeat the caching
somewhat by lowering TTL values on your records, but only at the expense
of increasing DNS traffic to the authoritative servers.

Hope that helps.

---

Query to DNS developers/architects: are there any plans to make a new
RR type for RRset ordering, so that slaves and caching servers can know
what ordering to use for a given RRset? I think this would be a valuable
feature.


- Kevin