Controlling which interface named uses

[Alessandro Vesely]

On Fri 09/Jun/2023 18:32:25 +0200 Anand Buddhdev wrote:
> On 09/06/2023 17:26, Alessandro Vesely wrote:
> 
>> Having two WANs, it would be reasonable, in case one doesn't work, to try the 
>> other one.  However, it's always useless to try the LAN.  Is there any way to 
>> configure which interface is used for outgoing queries?
> 
> You can configure "query-source" and "query-source-v6" in named.conf, to tell 
> BIND which interface to use for outgoing queries.


Thank you, Anand; I hadn't found those statements.  However, they take a single 
address only.

I'm not as much concerned about IP version as about availability.  Enabling 
IPv6 looks nice as I see queries going out through an interface which is not 
the default.  But will named turn back to the default interface in case the 
IPv6 link goes down?

Keep in mind that links sometimes seem to be up, as they're connected to a PPP 
peer or router, for example, but don't actually work.  Knowing that UDP entails 
multiple attempts, it would be great to have, say, even attempts on wan0 and 
odd ones on wan1.  If that's not possible, perhaps I could look for ways to 
configure it using dscp.  Any hint?


Best
Ale
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