EDNS Client Subnet (ECS) support in BIND 9.18-S1

[Greg Choules]

Hi Sami.
Have you tried `ecs-forward` in your BIND configuration? it will be
described in the -S ARM.

Cheers, Greg

On Tue, 3 Mar 2026 at 12:54, <sami.rahal at sofrecom.com> wrote:

>
>
> Hello,
>
> I am reaching out regarding the use of EDNS Client Subnet (ECS) in BIND.
>
> Context:
> I am testing an environment where:
>
>    - A dnsdist server receives client queries and injects a specific ECS
>    (e.g., 41.226.22.0/24).
>    - These queries are then forwarded to a BIND 9.18-S1 server configured
>    as the final resolver.
>
> Issue:
> BIND does not forward the ECS to upstream servers and does not preserve
> this information in responses.
>
> Questions:
>
>    - Can BIND 9.18-S1 be configured to rewrite or forward an ECS injected
>    by dnsdist?
>    - If not, which version or configuration would you recommend for BIND
>    to meet this requirement?
>
>
>
> Best regards Sami,
>
>
> --
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>
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