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

[sami.rahal at sofrecom.com]

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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