Determining Which Authoritative Sever to Use (Bob McDonald)

[Petr Špaček]

I have to warn you:
Authoritative server selection in DNS is not standardized, and thus it 
is not guaranteed to be stable even between BIND releases.

If you need to make static and/or optimal routing then you need to reach 
into IP routing layer for that.

Petr Špaček



On 08. 05. 22 18:57, Ben Croswell wrote:
> On the closest server question it will prefer the closest but a certain 
> percentage will go to servers further away. Additionally depending on 
> the version of BIND and the distance it could lead to the servers 
> further away taking more traffic in high QPS situations.
> 
> If you are getting high QPS you could fire off a large amount of queries 
> to the "slower" server before it responds and resets its SRTT. I believe 
> newer BIND versions have moved away from a static decrement value and 
> has fixed the issue but even fixes some queries will go out of region.
> 
> 
> On Sun, May 8, 2022, 12:47 PM Bob McDonald <bmcdonaldjr at gmail.com 
> <mailto:bmcdonaldjr at gmail.com>> wrote:
> 
>     Thanks for the answers. A couple more questions and then I'll
>     stand down.
> 
>     First, it's Ben Croswell. Just pointing that out.
> 
>     Second, my reading of the definition of a static-stub zone in the
>     Bvarmindicates that its use is to allow a local copy of the NS list
>     which may differ from the primary zone. I'm not sure that's what I'm
>     looking for. I think I'm ok with the NS list from the primary zone.
>     Lei me take another swing and try to be a bit more pedantic to see
>     if that helps.
> 
>     I wish to define a global internal DNS environment.
> 
>     At the level closest to the client would be a global network of
>     recursive DNS servers which would handle all internal and external
>     DNS requests. The internal DNS zones would be housed on a
>     global network of authoritative only DNS servers. The NS list for
>     the internal DNS zones on these authoritative only servers would be
>     known to the recursive servers via stub zones. My question is, if a
>     client in Mumbai submits a DNS request to his local recursive server
>     for an internal authoritative only zone defined by a stub zone
>     statement, which authoritative only server does the recursive server
>     pick from the NS list and will that eventually be the "closest"
>     server. I'm assuming a global distribution of the authoritative
>     servers. E.g. Hong Kong, London, US East, US West, South Amer, etc.
>     The use of the stub zones in this case is to eliminate the need for
>     an internal root. I want to avoid lookups for example from clients
>     in Asia being sent to authoritative only servers in South Amer.
> 
>     Bob