switching query-source address on timeout and exhaustion of available servers

[Giuliano Gavazzi]

On 12 Nov 2007, at 22:19, Kevin Darcy wrote:

> The only thing that comes immediately to mind is to run two  
> instances of
> named, one of which is locked to use only the ADSL as its query- 
> source.
> Then define the zones in question in the other instance as "type
> forward" to the "locked-down" instance. Make sure to define "forward
> first" for those zones, though (as opposed to "forward only"): in this
> way, if for some reason the queries are timing out or returning slowly
> from ADSL, the non-locked-down instance will fall back to attempting  
> to
> resolve the name _without_ using forwarding, which gives an extra  
> chance
> of resolution using the HDSL line as a query-source.

Thanks Kevin, that sounds interesting. I could even forget the ADSL  
and forward first to an external server (via the HDSL) that is on a  
different provider network. My problem after all is that of provider  
routing. Considering that the ADSL is unreliable (long distance) this  
might turn out more performing.

Giuliano