zlacker

In addition to what others mentioned, typically EDNS0 edns-client-subnet is truncated before forwarding.

For example in unbound the defaults, when EDNS0 is enabled (disabled by default), are:

  max-client-subnet-ipv6: 56
  max-client-subnet-ipv4: 24

Forwarding can also be conditionally enabled for specific clients, upstream servers, specific zones, etc.

ref: https://unbound.docs.nlnetlabs.nl/en/latest/manpages/unbound...