Description

header ensures that the flags are in the desired state for queries and responses. The modifications are made transparently for the client and subsequent plugins.

Syntax

header {
    SELECTOR ACTION FLAGS...
    SELECTOR ACTION FLAGS...
}

• SELECTOR defines if the action should be applied on query or response.

• ACTION defines the state for DNS message header flags. Actions are evaluated in the order they are defined so last one has the most precedence. Allowed values are:

  • set
  • clear

• FLAGS are the DNS header flags that will be modified. Current supported flags include:

  • aa - Authoritative(Answer)
  • ra - RecursionAvailable
  • rd - RecursionDesired

Examples

Make sure recursive available ra flag is set in all the responses:

. {
    header {
        response set ra
    }
}

Make sure “recursion available” ra and “authoritative answer” aa flags are set and “recursion desired” is cleared in all responses:

. {
    header {
        response set ra aa
        response clear rd
    }
}

Make sure “recursion desired” rd is set for all subsequent plugins::

. {
    header {
        query set rd
    }
}