Commit b7e91157 authored by Evan Hunt's avatar Evan Hunt
Browse files

revise "minimal-responses" documentation in the ARM

parent 7fff3295
......@@ -5809,30 +5809,55 @@ options {
<term><command>minimal-responses</command></term>
<listitem>
<para>
If set to <userinput>yes</userinput>, then when generating
responses the server will only add records to the authority
and additional data sections when they are required (e.g.
delegations, negative responses). This may improve the
performance of the server.
</para>
<para>
When set to <userinput>no-auth</userinput>, the
server will omit records from the authority section
unless they are required, but it may still add
records to the additional section. When set to
<userinput>no-auth-recursive</userinput>, this
is only done if the query is recursive. When the
query is not recursive, the effect is same as if
<userinput>no</userinput> was specified. These
settings are useful when answering stub clients,
which usually ignore the authority section.
<userinput>no-auth-recursive</userinput> is
designed for mixed-mode servers which handle
both authoritative and recursive queries.
</para>
<para>
The default is
<userinput>no-auth-recursive</userinput>.
This option controls the addition of records to the
authority and additional sections of responses. Such
records may be included in responses to be helpful
to clients; for example, NS or MX records may
have associated address records included in the additional
section, obviating the need for a separate address lookup.
However, adding these records to responses is not mandatory
and requires additional database lookups, causing extra
latency when marshalling responses.
<command>minimal-responses</command> takes one of
four values:
</para>
<itemizedlist>
<listitem>
<userinput>no</userinput>: the server will be
as complete as possible when generating responses.
</listitem>
<listitem>
<userinput>yes</userinput>: the server will only add
records to the authority and additional sections when
such records are required by the DNS protocol (for
example, when returning delegations or negative
responses). This provides the best server performance
but may result in more client queries.
</listitem>
<listitem>
<userinput>no-auth</userinput>: the server
will omit records from the authority section except
when they are required, but it may still add records
to the additional section.
</listitem>
<listitem>
<userinput>no-auth-recursive</userinput>: the same
as <userinput>no-auth</userinput> when recursion is
requested in the query (RD=1), or the same as
<userinput>no</userinput> if recursion is not
requested.
</listitem>
</itemizedlist>
<para>
<userinput>no-auth</userinput> and
<userinput>no-auth-recursive</userinput> are useful when
answering stub clients, which usually ignore the
authority section. <userinput>no-auth-recursive</userinput>
is meant for use in mixed-mode servers that handle both
authoritative and recursive queries.
</para>
<para>
The default is <userinput>no-auth-recursive</userinput>.
</para>
</listitem>
</varlistentry>
......
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