coredns.io/content/plugins/header.md

+++ title = "header" description = "header modifies the header for responses." weight = 23 tags = ["plugin", "header"] categories = ["plugin"] date = "2021-09-21T15:01:04.877489" +++

Description

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

Syntax

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

• 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 {
        set ra
    }
}

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

. {
    header {
        set ra aa
        clear rd
    }
}