Can someone clarify how the WAN DNS order works?

tommyv2

Regular Contributor
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Does DNS2 only get checked if DNS1 doesn't respond, or are the requests being round-robined between them? Would be nice to know or provide the option between those two behaviours. Thank you to anyone that knows the answer!
 

DHLarson

Occasional Visitor
I'm not certain of the designed intent during normal operation but it appeared, on initial power up, that the router sends out parallel queries at the same time. That behavior might only be during the initialization phase since that was when I was tracing the interface.
 

dave14305

Part of the Furniture
Every 50 queries or every 20 seconds (whichever comes first), dnsmasq will send a query to all its servers to see which are still responding and which might be fastest.

Otherwise, I think it just keeps sending to the last known working server, which should also end up being the fastest server to respond first.

There are custom options to alter the behavior, but this is how I believe it works as configured by the firmware.
 

sturmstar

Regular Contributor
@tommyv2 are you trying to achieve some specific result? Or just curious :)

Hi!

I just found this thread because I was searching somehting similar. And yes - I want to achieve something specific - I would like to set these as "Fallback only" - means I would like to achieve that only the first one is asked but if the first one isn't responding - THAN the second one is asked - and if the first one is "back" again - just ask the first one again.

Is this possible?

Thanks! Best regards
 

cptnoblivious

Senior Member
Hi!

I just found this thread because I was searching somehting similar. And yes - I want to achieve something specific - I would like to set these as "Fallback only" - means I would like to achieve that only the first one is asked but if the first one isn't responding - THAN the second one is asked - and if the first one is "back" again - just ask the first one again.

Is this possible?

Thanks! Best regards
That's not how DNS works, the client determines the order and you live with it :)

Pick 2 DNS servers that do the same thing (blocking / security whatever), list them both. If one goes off line or performance reduces, the other one will answer the same way.
 

ColinTaylor

Part of the Furniture
That's not how DNS works, the client determines the order and you live with it :)
In the context of this thread the client is dnsmasq running on the router. So to answer @sturmstar's question: no, dnsmasq does not have any options that enable fail-over and fallback.
 
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sturmstar

Regular Contributor
In the context of this thread the client is dnsmasq running on the router. So to answer @sturmstar's question: no, dnsmasq does not have any options that enable fail-over and fallback.

Thanks, yes - that's it what I meant - a pity that this isn't possible.

best regards
 

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